(con)juncture

juncture dictionary.com

  1. a point of time, especially one made critical or important by a concurrence of circumstances.
    At this juncture, we must decide whether to stay or to walk out.
  2. a serious state of affairs; crisis.
    The matter has reached a juncture and a decision must be made.
  3. the line or point at which two bodies are joined; joint or articulation; seam.
  4. the act of joining.
  5. the state of being joined.
  6. something by which two things are joined.
  7. Phonetics.
    a pause or other phonological feature or modification of a feature, as the lengthening of a preceding phoneme or the strengthening of a following one, marking a transition or break between sounds, especially marking the phonological boundary of a word, clause, or sentence: it is present in such words as night-rate and re-seed and absent in such words as nitrate and recede.

    the point in a word or group of words at which such a pause or other junctural marker occurs.

Juncture Wikipedia

Juncture thesaurus.com

juncture Collins

At a particular juncture means at a particular point in time, especially when it is a very important time in a process or series of events.

juncture synonyms Merriam-Webster Thesaurus

Critical juncture theory Wikipedia

...Critical junctures are turning points that alter the course of evolution of some entity (e.g., a species, a society). Critical juncture theory seeks to explain both (1) the historical origin and maintenance of social order, and (2) the occurrence of social change through sudden, big leaps.[3]

(Kuhn, Lipset and Rokkan, Gellner, Gould, Stinchcombe, et seq.)

juncture mnemonicdictionary.com

critical point, crossroads