Real Dictionary

trunk
An elephant's trunk is its very long nose that it uses to lift food and water to its mouth.
The trunk of a tree is the large main stem from which the branches grow.
countable noun: A trunk is a large, strong case or box used for storing things or for taking on a journey.
countable noun: The trunk of a car is a covered space at the back or front in which you put luggage or other things.
plural noun: Trunks are shorts that a man wears when he goes swimming.

trunk in American English
the main stem of a tree
adjective: of, pertaining to, or noting a main channel or line, as of a railroad or river
noun: the main stem of a tree, as distinct from the branches and roots

trunk in Automotive Engineering
noun: The trunk of a car is a covered space at the back or front in which you put luggage or other things.

trunk in British English
noun: the main stem of a tree, usually thick and upright, covered with bark and having branches at some distance from the ground