What is a word: Yes.
fun little story: I once visited a lecture called "what is a word?", and the lecturer started with a quizz presenting... well, pieces of speech and asking whether we would consider it a single word or not. Then they said that barely anyone changes their mind throughout their course, and that the answers would remain pretty much the same at the end π But it was still nice to learn about alllll the theories (there are a lot)