noun. The ability of words, signs and symbols to have multiple meanings.

noun. the ambiguity of an individual word or phrase that can be used (in different contexts) to express two or more different meanings

"And I'm not even talking about polysemy, which is the greedy habit some words have of taking more than one meaning for themselves."

monosemy  

homonymy  

polyseme  polysemic  polysemous  

ambiguity  equivocalness