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

Quick, at once or without delay.

M.E., from O.Fr. prompt, from L. promptus "brought forth, ready, quick," p.p. of promere "to bring forth," from → pro- "forward" + emere "to take."

Tond, "swift, rapid, brisk; fierce, severe," Mid.Pers. tund "sharp, violent;" Sogdian tund "violent;" cf. Skt. tod- "to thrust, give a push," tudáti "he thrusts;" L. tundere "to thrust, to hit" (Fr. percer, E. pierce, ultimately from L. pertusus, from p.p. of pertundere "to thrust or bore through," from per- + tundere, as explained); PIE base *(s)teud- "to thrust, to beat."
Biderang "without delay," from bi- negation prefix, → in-, + derang, → delay.

Neutrons emitted immediately by a nucleus undergoing fission, as opposed to → delayed neutrons, which are emitted by one of the fission products an appreciable time interval after the fission event (from a few milliseconds to a few minutes).

→ prompt; → neutron.

A mechanism predicted by theoretical models of → supernova explosion in the case when the → supernova shock breaks through the outer edge of the collapsing → iron core before losing all of its energy (through → photodisintegration of the iron nuclei) and manages to expel the stellar envelope. Compare with → delayed supernova explosion.

→ prompt; → supernova; → explosion. See also → delay.