There are (as of a few seconds ago) 481 questions with the between tag. Many of them are about SQL (and related tags), others are about C#, Java,
Frankly, I doubt if the tag provides any benefit. I suggest it should be burninated.
I came across it when I reviewed a proposed Wiki excerpt for the tag.
Update (2013-10-23): the Wiki now firmly reflects that between is for use with SQL.
Consequently, the questions that don't mention SQL but are tagged between should have the tag removed. I've done some, using queries like
[between] -[sql] but that still shows question tagged with specific DBMS instead of a generic SQL tag. You can extend the list of excluded tags with a search notation such as
[between] -[mysql] -[sql] -[tsql] -[sql-server] -[sqlite] -[sqlite3]. Some entries have been eliminated; there's a lot of weeding still to do.