Something that's always bothered me is that the word "transversal" is very commonly used as an adjective, but my understanding is that "transverse" is the correct adjective, and that "transversal" is a noun which means "an object which is transverse [to a given object]." So for example you would say "transverse intersection" and "pick a transversal for the line."

However, I could be wrong. I'd like people to answer with their opinion on which is the correct word for the adjective. I'm making this a community wiki since it's too soft to gain reputation over.