D defs.my
Entry 1 sense Webster, 1913

Half-ray

/(-rā`)/ · Half·-ray · IPA
01 n. A straight line considered as drawn from a center to an indefinite distance in one direction, the complete ray being the whole line drawn t…
  1. 1.
    A straight line considered as drawn from a center to an indefinite distance in one direction, the complete ray being the whole line drawn to an indefinite distance in both directions.(Geom.)