開かい口こう数すうMeaningsNoun1. numerical aperture (in photography)Kanji used開open口mouth数numberPitch accentかいこうすうComposed of開かい口こうopening; aperture (e.g. camera); opening one's mouth; beginning to speak; open; broadNoun数すうseveral; a few; a number of; number; quantity; amount; counting; calculation; figures; numbers; …Prefix