Akademik

кстати
нареч. to the point (or purpose) ;
opportune(ly) , in the nick of time;
apropos;
besides, too, as well;
incidentally, by the way быть кстати ≈ come in handy кстати и некстати ≈ in (season) and out of season, whether appropriately or not
нареч.
1. (уместно) to the point;
очень ~ very much to the point;
это очень ~! that is just what was wanted!;
it`ll come very handy!;
это случилось очень ~ it came in the very nick of time;

2. (заодно) while one is about it;
когда пойдёте гулять, ~ зайдите к нему while you`re taking your walk, you might as well drop in and see him;

3. в знач. вводн. сл. (между прочим) by the by, by the way;
incidentally;
~, где он сейчас? by the way, where is he?

Большой англо-русский и русско-английский словарь. 2001.