Several parts combine into one character.

度 combines 广 (a building) with a hand (又) inside it; from measuring length by hand came "to measure, a ruler, a standard, an extent." It began from the old practice of gauging length by handspans.

Korean hanja-sound "do" (also "tak"): 制度 (jedo, system), 溫度 (ondo, temperature), 角度 (gakdo, angle), 程度 (jeongdo, degree / extent), 態度 (taedo, attitude), 法度 (beopdo, law). When it means "to reckon" it is read "tak" — 忖度 (chontak, to surmise).

Mandarin: dù, 4th tone (degree) / duó, 2nd tone (to estimate). 温度 (wēndù, temperature), 角度 (jiǎodù, angle), 程度 (chéngdù, degree), 态度 (tàidù, attitude), 速度 (sùdù, speed) / 揣度 (chuǎiduó, to surmise). A one-character, two-sound case — "degree" is dù (4th), "to estimate" is duó (2nd).

Japanese: on-readings ド (do), ト (to), タク (taku), kun たび (tabi). 温度 (ondo, temperature), 角度 (kakudo, angle), 態度 (taido, attitude), 一度 (ichido, once), 支度 (shitaku, preparation — a タク reading), 度々 (tabitabi, often). In Japanese "~times" is counted 一度, 二度.

Memory aid: a hand (又) measuring length inside a building (广) — from measuring come law and degree.