角

contained angle; included angle

bevel

supplement

choppy sea; chopping waves

さんかくは only; Physics

triangle wave

viewing angle; viewing direction

trigonometry

hexagonal wrench; Allen key

make-or-break game in a go or shogi tournament

Sumo

ozeki-ranked wrestler being in danger of losing his rank if he fails to win 8 or more bouts in a 15-day tournament

chelicera; mouthparts of chelicerates (including arachnids)

frothing at the mouth

Astronomy

Spring Triangle (asterism)

playing shogi with a handicap of the rook and bishop

participating in a contest while missing key players, pieces, etc.

obtuse angle

to be really angry

hornless; polled

trilateral trade

high-angle

angle of intersection

square

baseball played without a second base (children's game)

triangulation

one-horned

declination; angle of deviation

Mathematics

argument (of complex number)

delta wing