tat 1  |tøt| verb  ( tat•ted  |tødəd|, tat•ting  |tødɪŋ|) [ trans. ]   make (a decorative mat or edging) by tying knots in thread and using a small shuttle to form lace. ORIGIN  late 19th cent.: back-formation from   tatting  .
via my mother again, the crossword champion.