Is this a date?

This guy I work with just suggested I meet him in the city for drinks tonight - he ll be with some friends too. Is it a date? I haven't met his friends before, but he has met mine. We hang out a bit outside of work, sometimes just the two of us, and while there's occasionally an 'atmosphere' between us, he's dated a couple of other girls in two years I've known him. He doesn't hang out with anyone else from work, outside of work.