1) Alley target 2) Bowling pin 3) Bowling target 4) Frequent spare target 5) Half of a certain split 6) It may foil a strike 7) Kind of bowling 8) One affected by a strike 9) One at the edge of the gutter 10) Rear target in bowling 11) Spare target 12) Spare target, sometimes 13) Split part, sometimes Found on https://www.crosswordclues.com/clue/tenpin