High card: highest card of five when there is no pattern.
Pair: two cards of the same rank, like two aces or two fours.
Two pair: two different pairs of cards, like two aces and two sixes.
Three of a kind: just like it sounds like. Three cards of the same rank, like three tens.
Straight: five cards, not of the same suit, in sequential order.
Flush: five cards of the same suit.
Full house: a three of a kind and a pair in the same five-card hand
Four of a kind: four cards the same rank.
Straight flush: five cards, in sequential order, of the same suit.
Royal flush: the five highest ranked cards (ten, jack, queen, king, ace) all of the exact same suit.