We already have "doubled" tags like lp and linear-programming.
Can we define standard tags or is it too early for that?
No, it isn't too early. If you notice tags that are duplicates, you want tags to be merged, synonymized, be removed, etc., come to Meta, here, ask a question with your request stated clearly and tag with discussion tags and synonym-request/retag-request/burninate-request.
A moderator will see the post and will proceed accordingly. Please note that you should ask one request per post!