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
