Facebook allows you to specify either the word "Like" or the word "Recommend" using the attribute: action="like"
in the code. But those are the only two. I'd prefer "Share" as well actually. But it can't be done.
Using "recommend" sounds like it would remove the ambiguity. However, my guess is that many (most?) Facebook users will not have come across "recommend" often enough, and may take it to be completely different to "like".