Tag Question

Hi everyone,

I have a technical question about tagging. Does Etsy use tags exactly or does it account for slight variations? The two I'm wondering about in particular are if it's important to have both bookmark and bookmarks and watercolour and watercolor. I'm Canadian so obviously the former spelling is what I'm used to but I don't want to have my listings hidden from US buyers by not accounting for their spelling. Just want to make sure I'm using the tags as effectively as possible!