In linguistics, a homonym is a group of similar words that have different meanings. There are two kinds of homonyms; homophones and homographs. A homophone is a word that is pronounced the same as another word but differs in meaning, and may differ in spelling. A homograph is a word that shares the same written form as another word but has a different meaning. 

Homophones are punny and can add more impact than using the correct word. The seemingly wrong word used makes people double take, and think more in depth about what the trade sign means or just generally laugh at the ‘mistake’ in the sentence. 

Punny or not?  You decide.