What's the term for when two related words are used in a different sense, often one literally and one metaphorically?
Apologies for the title, I found it difficult to describe.
If I say he took his hat and his leave I believe that is called syllepsis or zeugma. Another example would be he bolted his food, the door, and down the street.
But is there a term for an expression like where the gin is cold but the piano's hot?
Cold is used literally, hot metaphorically. It seems related to the first examples or does it have a more specific name - or no name at all?
I think, in the general sense, you're describing a pun—specifically, a homonymic (or polysemic) pun. From Wikipedia:
Homonymic puns, another common type, arise from the exploitation of words which are both homographs and homophones. The statement “Being in politics is just like playing golf: you are trapped in one bad lie after another” puns on the two meanings of the word lie as “a deliberate untruth” and as “the position in which something rests”…A homonymic pun may also be polysemic, in which the words must be homonymic and also possess related meanings, a condition that is often subjective.