zero degrees Celcius, freezing point / zero degrees (other scales)

Clipping of 零式艦上戦闘機 (Rei-shiki Kanjō Sentōki, “Type 0 Carrier Fighter: Mitsubishi A6M Zero”).

a male given name

a zero vector

zero-sum

so many men, so many minds

one-hundred fires and one-hundred hits: making the mark every time

Used other than figuratively or idiomatically: see 一 and 本 (one thing) / Short for 一本勝ち (ippon-gachi, “winning in one blow”).

a comic book, a cartoon book

hardcore pornography; 'underground' pornography showing uncensored genitals. Technically illegal in Japan.