Definition of train
1 a
: a connected line of railroad cars with or without a locomotive
b
: an automotive tractor with one or more trailer units
3 a
: an orderly succession
- a train of thought
b
: order of occurrence leading to some result
—often used in the phrase in train
- this humiliating process had been in train for decades
- —Paul Fussell
c
: accompanying or resultant circumstances : aftermath
- consequences the discovery will bring in its train
4
: a series of moving mechanical parts (such as gears) that transmit and modify motion
- a gear train
5
: a part of a gown that trails behind the wearer
6
: the vehicles, personnel, and sometimes animals that furnish supply, maintenance, and evacuation services to a combat unit
7
: a series of parts or elements that together constitute a system for producing a result and especially for carrying on a process (as of manufacture) automatically
8
: a line of combustible material laid to lead fire to a charge
