semiangle

noun

1. an angle of half a given size
2. The angle formed between the axis of a cone and a line drawn from the apex of the cone to the edge of its base.

   “The results show that the optimum cone semiangle decreases slightly when the Mach number increases and, in the range of Mach numbers considered, is in the range of 22° to 25° for supersonic entrance flow.”

   “The author's theory is almost perfect for 5° semiangle, is good for M_∞ ≤ 2 with 10° semiangle, and is beginning to be a serious overestimate for 15° semiangle.”

   “Variations in cone semiangle had no significant effects on the longitudinal stability at the two test Mach numbers .”