Combo

math

A specific 2-card hand combination (e.g. A♠K♦).

AA has 6 combos, AKs has 4, AKo has 12. Counting combos lets you compute exact range frequencies.

See also

Equity
Your statistical share of the pot, expressed as a winning probability.
EV
The average profit/loss of a play over infinite repetitions.
Implied Odds
Pot odds adjusted for expected future bets if you hit your draw.
Outs
Cards remaining in the deck that improve your hand to a winner.