STEM-WINDER is a term used to describe an especially long and passionate speech. It is derived from the phrase 'wind up a stem, ' which refers to winding up a clockwork mechanism, such as a watch or clock, to make it run. The term is often used to describe a speech that is so long and passionate that it seems to have been wound up like a clockwork mechanism. The crossword solution for STEM-WINDER is ORATION, which is a formal speech, usually given in a public setting.