Backdoor Flush

draws

Having one card to a flush on the flop.

Adds ~4% equity. Useless alone but matters for combo equity in semi-bluffing decisions.

See also

Backdoor
A draw needing two perfect cards (turn + river) to complete.
Drawing Dead
Having no card left in the deck that can win the hand.
Flush Draw
Four cards of the same suit, needing one more for a flush.
Gutshot
An inside straight draw — needing one specific rank (4 outs).