Clickbait title: This editor describes basic vocabulary and you won't believe what happens next! Filmmakers are actually really awful when it comes to vocabulary, re-using words randomly, basically describing anything with whatever word feels right at the time. A gobo is a cucalorus, also called a cookie, that has a focusing mechanism, but a gobo is also a kind of motor, and that motor might be attached to a gobo, or it might be attached to the fixture itself, and by the transitive properties of metonyms you end up with a gobo gobo with a gobo on its gobo. I've seen 'parallel cut' used at least three different ways in various textbooks and glossaries. This isn't me claiming that I've got the definitive take on all of these terms, just that, you know, if you heard a term used a different way to describe a different thing chances are you're right, you have and you did, because it's a mess and we're all faking it.