Frame: One turn of a game. A bowler gets two chances to knock down all the pins in a frame.
Strike: When the bowler knocks all the pins down in the first ball of a frame. It is scored by putting an X in the small box of the frame.
Spare: When a bowler knocks all the pins down using both shots in a turn. It is scored by putting a diagonal line in the small box of the frame.
Pin Count: How many pins are knocked down on the first ball when the bowler does not strike. It is marked on the score card in the first small box or in front of the small box when the score card has only one small box.
Headpin: The number 1 pin. It is the closed pin to the bowler and is in the center of the lane.
Split: When a bowler leaves pins that are spread apart and the headpin is not standing. It is usually indicated on the score sheet with a circle around the first ball pin count.
Washout: Looks like a split but the headpin is still standing.
Makeable Spares: Spares that are not splits or washouts.