Refers to a large travel case, often a hard-sided suitcase or a classic trunk. The English word 'trunk' in this sense is less common in modern Japanese.
I bought a new suitcase for the trip.
Commonly used for the rear storage compartment of a car. 'Boot' is British English; 'trunk' is American English.
トランクに荷物を入れてください。
Please put the luggage in the trunk.
trunk line
Technical term for a main communication line or circuit. Often appears in compounds like トランク回線.
このシステムはトランク回線で接続されている。
This system is connected via a trunk line.
My father opened the car trunk and took out the luggage.
We put the suitcase in the trunk and set off.
Before the trip, I loaded the luggage into the trunk.
The night before departure, she packed her trunk.