From Longman Dictionary of Contemporary Englishtrunktrunk /trʌŋk/ ●●● S3 noun [countable] 1 
treeHBP the thick central woody stem of a tree He left his bicycle leaning against a tree trunk.trunk of the trunk of an old oak tree2 car American EnglishTTC the part at the back of a car where you can put bags, tools etc SYN boot British English Put your suitcase in the trunk.3 elephantHBA the very long nose of an elephant4 clothes swim trunks American English, swimming trunks British English [plural]DCC a piece of clothing like very short trousers, worn by men for swimming5 
boxDH a very large box made of wood or metal, in which clothes, books etc are stored or packed for travel6 body technicalHBH the main part of your body, not including your head, arms, or legs SYN torso → suitcase
treeHBP the thick central woody stem of a tree He left his bicycle leaning against a tree trunk.trunk of the trunk of an old oak tree2 car American EnglishTTC the part at the back of a car where you can put bags, tools etc SYN boot British English Put your suitcase in the trunk.3 elephantHBA the very long nose of an elephant4 clothes swim trunks American English, swimming trunks British English [plural]DCC a piece of clothing like very short trousers, worn by men for swimming5 boxDH a very large box made of wood or metal, in which clothes, books etc are stored or packed for travel6 body technicalHBH the main part of your body, not including your head, arms, or legs SYN torso → suitcaseExamples from the Corpus
trunk• Barbara Molland had found the box in a trunk that stood under the window in Kate's room.• Parked on his trunk, Mitchell finished reading the Miami HemId; both the crowd and his optimism began to thin out.• As the phrase suggests, a main trunk of cables splits off into branches which supply individual subscribers.• His powerful trunk and huge belly filled the chair and the yellow cattleman's boots were laced half way up the stout legs.• She knelt by the trunk, flinging aside papers, reaching down and down, scrabbling in the corners.• She stepped on the emergency brake and got out to help Paul get his suitcase in the trunk.• One wanted me to open the trunk.• Now, this tree is aberrant in that it has two trunks.tree trunk• Unfortunately, the Brownsea red squirrels are also nervous; generally they get behind a tree trunk when they hear people approach.• Although they do not need it to fight they are usually armed with a big club made from a tree trunk.• A mourning cloak butterfly flew up from a tree trunk in the sunshine where it was basking.• Forty feet away was a nest box fixed to a tree trunk at a height of 8 feet above the ground.• Hiding in the swamp, Sammler lay under a tree trunk, in the mud, under scum.• My ankles were like tree trunks and I could just about reach the model because I was so big.• In addition, the tree trunks are ringed with bright green growths at their bases.• And the tree trunks to black.Origin trunk (1400-1500) Old French tronc “box, main part of a body”, from Latin truncus “tree-trunk, main part of a body” 