A search for 'firste stock' finds the (quite long) entry for 'stock'; see the 3. sense for mention of Chaucer's use in
"Gentilesse":
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> stock
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> stock sto(hook)k, sb.1 Forms: 1 stocc, 1-4, 6 stoc, 2-7 stoke, 3-7
> stocke, stok(ke, (5 ? stolke), 5-6 stokk, 7 Sc. stouk, 4- stock. Pl.
> 3 stocken, 4 stockus, stokez, stokken, stokkus, stoukz, 4- 5
> stokkez, 4-6 stockys, stokkes, 4-7 stockis, stok(k)is, 5-6 stokkys,
> 6 stokys, 7 stox. OE. stoc(c masc., corresp. to OFris. stok
> tree-trunk, stump, OS. stok (Gallée) stick, pole (MLG. stok stump),
> (M)Dutch stok, OHG., MHG. stoc stick, tree-trunk (mod.G. stock
> stick), ONor. stokk-r tree-trunk, block, log (MSw. stokk-er, Sw.
> stock, Da. stok stick):-OTeut. *stukko-z. Cf. Dutch stuk, G. stuck
> (:-OTeut. *stukkjo-m neut., piece) and OFris. stok stiff. The
> connexions outside Teut. are doubtful: see Kluge, Franck, and Falk &
> Torp; The Teut. word is the source of OFr., Pr. estoc trunk, stump
> (mod.Fr. étoc, altered to étau vice), Ital. stocco rapier (whence
> OFr. estoc).
>
> A. sb.
>
> I. Trunk or stem.
>
> 1.
>
> a. A tree-trunk deprived of its branches; the lower part of a
> tree-trunk left standing, a stump. Obs. or arch.
>
> In this sense (also in b and c) often associated with stone.
>
> * 862 Charter in O.E. Texts 438 Danne fram langan lea(asg)e to
> dam won stocce.
>
> * 971 Blickling Hom. 189 He (asg)efeol on pone stocc be pære
> stænenan stræte pe is háten Sacra uia;
>
> * 11.. Fragm. Ælfric's Gram; (1838) 3 Ligna, dri(asg)e wude,
> truncus, stoc, stirps.
>
> * C. 1250 Owl & Night; 25 Tho stod on old stok par byside.
>
> * C. 1325 Sir Orpheo 332 Over stok, and over stone.
>
> * C. 1374 Chaucer Boeth. v. met. i. (1868) 152 The stokkes araced
> wip pe flood [L. vulsi flumine trunci].
>
> * C. 1480 Henryson Orpheus 179 For seke hir suth I sall, and
> nouthir stynt nor stand for stok no stone.
>
> * 1509 Barclay Ship of Fools 269 b, Hange vp the scapler..Vpon a
> tre clene dede, or rottyn stocke.
>
> * 1590 Spenser F.Q. i. ix. 34 All about old stockes and stubs of
> trees, Whereon nor fruit nor leafe was euer seene.
>
> * 1613 [Standish] New Direct. Planting 6 Seldome good Timber
> groweth of old stockes.
>
> * 1704 N. Blundell Diary (1895) 22, I ploughed with a Culter..to
> find Stocks.
>
> * 1706 De Foe Jure Div. xi. 9 note, If the Parliament of England
> sets the Crown upon that Stock, (pointing to a Stump that stood
> by) I'll [etc.].
>
> * 1727 Swift Poems Market-hill, Thorn 33 The magpye, lighting on
> the stock, Stood chatt'ring.
>
> * 1810 Scott Lady of L. i. vii, O'er stock and rock their race
> they take.
>
> * 1837 Carlyle Fr. Rev. II. iv. vii, Over cliffs, over stock and
> stone.
>
> * 1868 Cussans Heraldry (1893) 104 The Stump of a Tree is
> sometimes called a Stock.
>
> * 1877 Stevenson Will o' the Mill i, Only he, it seemed, remained
> behind, like a stock upon the wayside.
>
> b. A log, block of wood; occas. wood as a material. Obs.
>
> * C. 1000 Ælfric Saints' Lives xxxi. 856 Thær la(asg)on stoccas;
>
> * C. 1205 Lay. 626 Mid stocken & mid stanen stal fiht heo
> makeden;
>
> * C. 1386 Chaucer Knt's. T. 2076 Ne how the fyr was couched first
> with stree And thanne with drye stokkes clouen a thre.
>
> * 1422 Yonge tr. Secreta Secret. 239 Suche a stomake is like a
> grete fyre that hath Powere to braunte grete shydis and
> stokkis.
>
> * C. 1450 St. Cuthbert (Surtees) 780 Made of stane and no3t of
> stok.
>
> * C. 1485 Digby Myst. i. 154, I am right wele a-paid, if I do not
> wele, ley my hed vpon a stokke.
>
> * 1501 Douglas Pal. Hon. ii. xxvii, Doun on ane stock I set me
> suddanelie.
>
> * 1610 Holland Camden's Brit. (1637) 251 A stocke of wood
> hollowed [for a coffin].
>
> * 1792 G. Cartwright Jrnl. Labrador I. Gloss. p. xv, Stock of
> Timber, a piece of timber, intended to be sawed.
>
> * 1806 Pike Sources Mississ. (1810) 61 My men sawed stocks for
> the sleds.
>
> c. As the type of what is lifeless, motionless, or void of
> sensation. Hence, a senseless or stupid person.
>
> * 1303 R. Brunne Handl. Synne 940 Dowun he smote hys mattok, And
> fyl hym self ded as a stok.
>
> * C. 1330 Arth. & Merl; 3855 Arthour on hors sat stef so stok.
>
> * C. 1407 Lydg. Reson & Sens; 6411 As deffe as stok or ston.
>
> * C. 1440 Alphabet of Tales 356 Evur sho talkid vnto hym wurdis
> to provoce hym to luste of his bodie, and yit be no wyse myght
> sho induce hym perto,..he was a stokk, sho sayd, & no man;
>
> * 1569 Underdowne Heliodorus iv. 59 Yee vnhappy people, howe
> longe will ye sitte still, dombe like stockes?
>
> * 1594 Spenser Amoretti xliii, That nether I may speake nor
> thinke at all, But like a stupid stock in silence die!
>
> * 1640 Sir E. Dering Carmelite (1641) B ij, I am not so credulous
> to thinke every Stock a Stoicke.
>
> * 1644 Milton Educ. 3, I doubt not but ye shall have more adoe to
> drive our dullest and laziest youth, our stocks and stubbs from
> the infinite desire of such a happy nurture then we have now
> [etc.].
>
> * 1714 Lady M. W. Montagu Let. to Mrs. Hewet Nov. (1887) I. 35, I
> am glad she is not such a stock as I took her to be.
>
> * 1719 De Foe Crusoe ii. (Globe) 344 The Fellow stood mute as a
> Stock a good while.
>
> * 1775 Sheridan Rivals iii. i, What a phlegmatic sot it is! Why,
> sirrah, you're an anchorite!-a vile, insensible stock.
>
> * 1809 Malkin Gil Blas ix. vi. (Rtldg.) 320, I..left him in the
> street like a stock, staring at my termagant loquacity.
>
> * 1861 Dickens Gt. Expect. xxxviii, You stock and stone!.. You
> cold, cold heart!
>
> * 1888 Barrie When Man's Single i, Joey Fargus was the stock's
> name.
>
> * 1896 K. Snowden Web of Weaver xviii. 207 `Ye are not fain to
> see me, then?' I stood like a stock, letting her think so.
>
> d. Applied contemptuously to an idol or a sacred image. Chiefly in
> the phrase
>
> stocks and stones
>
> stocks and stones = `gods of wood and stone'.
>
> * C. 1000 Ælfric Deut. xxviii. 36 (Asg)e peouiad fremdum godum,
> stoccum and stanum.
>
> * A. 1225 St. Marher. 1 Hedene mawmez of stockes, ant of stanes,
> werkes iwrahte.
>
> * C. 1374 Chaucer Troylus iii. 589 He swor hir, yis, by stokkes
> and by stones, And by the goddes that in hevene dwelle.
>
> * 1390 Gower Conf. II. 178 How myhte a mannes resoun sein That
> such a Stock mai helpe or grieve?
>
> * C. 1449 Pecock Repr. ii. ix. 198 Thei worschipiden ymagis of
> stoonys or of stockis.
>
> * 1529 More Dyaloge i. Wks. 140/1 Of al our Ladies saith one, I
> loue best our Lady of Walsingam. And I saith ye other our Lady
> of Ippiswitch. In whiche woordes what meneth she but
> her..affeccion to the stocke yt standeth in the chapel of
> Walsingam or Ippiswiche.
>
> * A. 1591 H. Smith Sinful Mans Search (1592) B 6, That ye be not
> seduced to offer your petitions to strange gods, as Saints,
> stockes or stones.
>
> * 1611 Bible Jer. iii. 9, Wisd. xiv. 21.
>
> * 1640 J. Taylor (Water P.) Differing Worships 4 Imploring
> aid..From ragges and reliques, stones, and stocks of wood.
>
> * 1655 Milton Sonn. xiii. 4.
>
> * 1825 Scott Talism. xxviii, Those whom we regard as idolaters,
> and worshippers of stocks and stones.
>
> * 1874 Sayce Compar. Philol. viii. 332 There was a worship of
> nature instead of stocks and stones.
>
> e. (
>
> to lose stock and block
>
> to lose) stock and block: everything, one's whole possessions. Obs.
>
> * 1675 Brooks Golden Key Wks. 1867 V. 244 Adam, like the prodigal
> son,..quickly lost stock and block, as some speak.
>
> * 1725 N. Bailey Fam. Colloq. Erasm. (1733) 236 Before I came
> Home, I lost all, Stock and Block.
>
> * 1775 J. Murray Lett. (1901) 194 Jack Clark..offered to send
> Providence wagons to move us stock and block to a place of
> safety.
>
> * 1809 Malkin Gil Blas xii. vi. (Rtldg.) 431, I had taken it for
> granted that..the verb-grinders..to whom I had given the plant
> of this Genoese bastard would lose stock and block.
>
> f.
>
> stock and stovel
>
> stock and stovel (Law): see quot. 1753. Obs.
>
> * ? 15.. Charter in Blount's Law Dict. (1691) s.v. Stoc, Præterea
> si homines de Stanhal dicti Abbatis inventi fuerint in bosco
> prædicti W. cum forisfacto ad Stoc & ad Stovel,..malefactor pro
> delicto, qui taliter inventus est, reddet tres solidos;
>
> * 1753 Chambers' Cycl. Suppl., Stoc and Stovel, in our old
> writers, a forfeiture where any one is taken carrying stipites
> and pabulum out of the woods.
>
> 2.
>
> a. The trunk or stem of a (living) tree, as distinguished from the
> root and branches.
>
> to sell wood upon the stock
>
> (to sell wood) upon the stock: standing.
>
> * 1340 Hampole Pr. Consc. i. 676 What es man in shap bot a tre
> Turned up pat es doun,..The stok nest pe rot growand Es pe
> heved with nek folowand.
>
> * 1382 Wyclif Job xiv. 9 His stoc at the smel of water shal
> burioune.
>
> * C. 1430 Pilgr. Lyf Manhode iii. xxi. (1869) 146 Sumtime the
> wodieres solden here wode up on the stok.
>
> * C. 1449 Pecock Repr. i. vi. 28 Tho bowis grewen out of stockis
> or tronchons, and the tronchons or schaftis grewen out of the
> roote.
>
> * A. 1500 in Arnolde's Chron. 168 Doo donge medlide with strawe
> aboute the stoke toward the roete of a good thiknes.
>
> * ? A. 1500 Bollarde in Turner Dom. Archit. (1851) I. 144 Take
> many rype walenottes, and water hem a while,..and ther shalbe
> grawe therof a grett stoke, that we calle masere.
>
> * 1526 Pilgr. Perf. (W. de W. 1531) 43 Of the whiche tree, fayth,
> hope, & charite, be compared to the stocke, to the barke, & to
> the sap;
>
> * 1688 Holme Armoury ii. 84/2 The Stock [of a tree is] next to
> the root.
>
> * 1697 Dryden Virg. Georg. ii. 264 Strong Stocks of Vines it will
> in time produce.
>
> * 1705 tr. Bosman's Guinea 291 The Stock of these Trees, if they
> deserve that name, grow to once and a half or twice Man's
> height.
>
> * 1846 Tennyson Golden Year 62 Like an oaken stock in winter
> woods.
>
> * 1857 Henfrey Elem. Bot. Sect.57 The Stock or caudex is an
> undivided woody trunk.
>
> fig.
>
> * 1340 Ayenb. 19 The oper bo3 pet comp out of pe stocke of prede
> zuo is onworpnesse.
>
> * 1447 Bokenam Seyntys, Anna 110 Of this floure..This gracyous
> Anne was stoke & rote;
>
> * 1513 Bradshaw St. Werburge i. 3163 The tryed stock of truth and
> the grounde of grace Is pyteously decayed.
>
> * 1531 Tindale Expos. 1 John (1537) 54 As ther is no synne in
> Christ ye stock, so can ther be none in the quycke membres that
> lyue & grow in him;
>
> * A. 1536 Songs, Carols etc. (E.E.T.S.) 6 The blessid stoke pat
> yt on grew, Ytt was Mary, that bare Jhesu.
>
> * 1647 Cowley Mistress, Tree iii, What a few words from thy rich
> stock did take The Leaves and Beauties all?
>
> * 1812 Cary Dante, Parad. iv. 126 Thence doth doubt Spring, like
> a shoot, around the stock of truth.
>
> * 1884 tr. Lotze's Metaphysic i. iv. 89 The impossibility..of
> attaching the manifold of change by a merely outward tie to the
> unchangeable stock of the Thing.
>
> b. The hardened stalk or stem of a plant. (Jam.) Chiefly Sc.
>
> * 1629 Orkney Witch Trial in N.B. Advertiser Oct. 1894, [He] baid
> his wyff geve yow thrie or four stokis of kaill.
>
> * 1783 Burns Death Poor Mailie 38 To slink thro' slaps, an' reave
> an' steal, At stacks o' pease, or stocks o' kail.
>
> * 1913 J. G. Frazer Golden Bough (ed. 3) Balder II. xi. 193
> One..gave him several severe blows with the stock of a plant.
>
> c. Bot. = rhizome.
>
> * 1831 Macgillivray tr. A. Richard's Elem. Bot. ii. 47 The Stock
> or Rhizoma. This name has been given to the subterranean and
> horizontal stems of perennial plants, entirely or in part
> concealed under ground.
>
> * 1863 Oliver Bot. (1873) 5 A portion of the stem, which is
> thickened and more or less buried underground,..is called the
> stock.
>
3. Figurative uses developed from sense 2.
>
> a. The source of a line of descent; the progenitor of a family or
> race. In Law, the first purchaser of an estate of inheritance.
>
> * C. 1393 Chaucer Gentilesse 1 The firste stok, fader of
> gentilesse.
>
> * A. 1425 Cursor M. 9240 (Trin.) Thus was pe ton pe toperes stok.
>
> * C. 1440 Jacob's Well 49 In ony of pise thre lynes afore-seyd,
> go to pe stok, pat is fadyr or modyr, & noumbre no3t hem, but
> pe first persone, pat comyth of pat stok is pe first degre;
>
> * 1526 Pilgr. Perf. (W. de W. 1531) 210 Go to ye stocke of our
> progeny, & consyder it well;
>
> * 1583 Melbancke Philotimus D iij, If a man should desire an
> herauld to sift out her pettigree,..her stock would be found to
> be the maine sea, wereof she is nothing but the ouerture and
> ofscombe.
>
> * 1594 T. B. La Primaud. Fr. Acad. ii. 15 Hee that was the stocke
> of all mankinde.
>
> * 1620 T. Granger Div. Logike 292 The common stocke in a Kindred,
> or Tribe, is the Father, and Mother from whence the whole
> progeny, or issue is deriued.
>
> * 1667 Milton P.L. xii. 7 Thus thou hast seen one World begin and
> end; And Man as from a second stock proceed.
>
> * 1765 Blackstone Comm. I. iii. 210 The title to the crown
> is..not quite so absolutely hereditary as formerly; and the
> common stock or ancestor, from whom the descent must be
> derived, is also different. Formerly the common stock was king
> Egbert; then William the conqueror.
>
> * 1871 Freeman Norm. Conq. xviii. (1876) IV. 249 But one of
> Swegen's many sons might well become the stock of a new
> dynasty.
>
> * 1886 F. W. Maitland in Law Q. Rev. Oct. 485 To constitute a new
> stock of descent a very real possession was necessary.
> ....
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