Meaning of “trailer” - Learner’s Dictionary

trailer

noun [ C ] uk us /ˈtreɪlər/
CONTAINER

a container with wheels that can be pulled by a car or a truck

HOUSE mainly US

a house on wheels that can be pulled by a car

FILM

short parts of a film or television programme which are shown in order to advertise it

(Definition of “trailer” from the Cambridge Learner’s Dictionary © Cambridge University Press)