Chemistry. (of a substance, as a vapor) to carry along (a dissimilar substance, as drops of liquid) during a given process, as evaporation or distillation.
2.
(of a liquid) to trap (bubbles).
3.
Meteorology. to transfer (air) into an organized air current from the surrounding atmosphere (opposed to detrain).
Origin: 1560–70; < Middle French entrainer, equivalent to en-en-1 + trainer to drag, trail; see train
1560s, from Fr. entrainer, from en- away + trainer to drag (see train (n.)). Related: Entrained; entrainment. A word in chemistry; the word meaning to get on a locomotive train is from the 1860s.