noun. the formation of a word from a sound associated with what is named
Aside from being remarkably hard to spell, this is one of those writing acts that can be very useful but very easy to overuse.
When something BAM! crashes into something else, or air HISS escapes through an airlock, or SQUELCH someone sinks into mud…
Sometimes dotting these around to parts of your prose can be good and make an impact BAM! but do it too much and your book starts reading like a comic book.
But if that’s what you’re going for, be my guest!