An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1a) (n.) Anything, as an act or event, that serves as a stimulus and initiates or precipitates a reaction or series of reactions.
1b) In electronics, the signal or stimulus that initiates a → trigger circuit.
2) (v.) To initiate or precipitate (a chain of events, scientific reaction, psychological process, etc.).

Earlier tricker, from Du. trekker "trigger," from trekken "to pull," from M.Du. trecken (cf. M.L.G. trecken, O.H.G. trechan "to draw").

1) Mâšé "a trigger, tongs, pincers," of unknown origin.
2) Mâšidan, infinitive from mâšé, as above.

A circuit in which a specific predetermined action is initiated by an input pulse.

→ trigger; → circuit

The formation of second-generation stars in a → molecular cloud, as set off by the action of → massive stars. → sequential star formation; → radiation-driven implosion.

→ trigger; → star formation.