Definition of half-move in US English:

half-move

noun

Chess
  • A move made by one player (especially in the context of the analysis of play made by a chess-playing computer program).

    • ‘Change its thinking depth to one or two ply (half-moves) or only a few seconds (Menu ‘Play’ ‘Set up Game Details’ use ‘Different Time Controls’ and set them to a low value).’
    • ‘In other words, there is no sense looking 10 ply (half-moves) down a line where the 3rd or 4th reply is implausible instead of considering either.’

Pronunciation

half-move

/ˈhafˌmo͞ov/