One way to hold this word: six things standing side by side and counted as one. Six cans in a plastic ring are the picture everyone starts from — you pick them up with one hand and pay for them once. After that the word travels by look and by count. Anything that shows up as six units in a row can borrow the name, whether it is muscle, metal or paper.
Three branches
綁成一件的六罐
最原始的那一組，其他用法都是從這個畫面借過去的。
noun · B1
A set of six cans or bottles of a drink held together in one pack and sold as a single item; it is used most often of beer, and also of soda, juice or water. People stretch it to any six things sold or grouped together.
六罐裝
看起來像六罐並排
這一支走的是外形：不是真的六罐，而是長得像六罐排在一起。
noun · B2
The stomach muscles of someone who trains hard, seen as six raised blocks under the skin; the word is a joke, because they look like six cans packed together.
六塊肌
行業裡的「一組六個」
這一支走的是數目：某個行業需要把六個單位湊成一組使用，就直接沿用這個名字。兩個用法都帶著自己的領域標記，離開那個場合就聽不到。
noun · C2
In the United States, a set of six photographs shown to a witness by the police, one of which is of the person they suspect, so that the witness can say whether they recognise anyone.
六人指認照片組