Definition
Plain language
The first betting round in a hand of poker, before any shared cards have been dealt.
As stated in the literature
The opening betting round in Texas Hold'em, after players receive their two private cards but before the flop; PokerSkill's deterministic context engine retrieves the relevant opening-range tables for this stage.
Also called: pre-flop, Preflop
Why it matters: It is the first decision point that shapes the whole hand, and standard opening ranges for this stage guide much of solid poker play.
For example, preflop a player looks only at their two private cards and decides whether to fold, call, or raise before any shared cards appear.