Several parts combine into one character.

化 combines an upright person (亻) with an inverted person (匕) — one person turned over into a different form, hence "to change, to become, transformation." The leading account sees in the contrast of standing and lying, living and dead, the sense of "metamorphosis."

Korean hanja-sound "hwa": 變化 (byeonhwa, change), 化學 (hwahak, chemistry), 文化 (munhwa, culture), 進化 (jinhwa, evolution), 惡化 (akhwa, worsening), 消化 (sohwa, digestion), 化粧 (hwajang, makeup). "~化 (hwa)" is the commonest suffix for "-ization" — 近代化 (modernization), 自動化 (automation).

Mandarin: huà, 4th tone. 变化 (biànhuà, change), 文化 (wénhuà, culture), 化学 (huàxué, chemistry), 现代化 (xiàndàihuà, modernization), 消化 (xiāohuà, digestion). The "-ization" suffix of modern Chinese is all 化.

Japanese: on-readings カ (ka) and ケ (ke), kun ば.ける (bakeru) and ば.かす (bakasu). 文化 (bunka, culture), 変化 (henka, change), 化学 (kagaku, chemistry), 化粧 (keshō, makeup — a ケ reading), お化け (obake, a ghost / monster). The kun 化ける (bakeru) means to transform or shape-shift — 狐が化ける (a fox transforms).

Memory aid: a standing person (亻) and an inverted person (匕) — turned over into a different form.