十

twentieth day of the first month (end of New Year celebrations, upon which remaining New Year's food is eaten, decorations are stowed away, etc.)

hookworm

32nd anniversary of death

decathlon

Anatomy

anterior cruciate ligament; ACL

Buddhism

the sixteen arhats

the 64 hexagrams (of the Book of Changes)

the pace of change makes ten years back seem like ancient history

Nagoya (and surrounding areas) dialect

a long time (since the last time); it's been a while (since I last saw, mailed, etc., you)

thirty-three temples in the Kinki area containing statues of Kannon (Avalokitesvara)

thirty-three temples sacred to Kannon (Avalokitesvara)

Buddhism

limitless time and space

lost decade (esp. of Japan, 1992-2002); decade of economic stagnation

carbon-14

Proverb; Abbreviation

even homely girls look beautiful at the peak of their youth

Mathematics

sexagesimal; base 60

Mathematics

duodecimal system; base twelve system

Chemistry

cesium-137; caesium-137

Idiomatic expression

beginning to learn (something) when one is old; not being too old to learn

Astronomy

Crux (constellation)

Computing

hexadecimal; hexadecimal notation; hex

soba eaten at the end of the month (esp. at the end of the year)

Mathematics

icosahedron

twenty questions (game)