Several parts combine into one character.

Compound ideograph: 八 (split / divide) on top + 牛 (cow / ox) on bottom = half. The ancient farming image: a single cow divided into two equal parts. Where 分 (the previous entry) abstractly says "divide into pieces", 半 specifically encodes "divide into TWO equal halves". The 牛 has stylized over millennia until it's no longer obviously a cow, but the meaning persists. Identical across 繁體 / 新字体 / 简体.

Mandarin: bàn, falling 4th tone. 一半 (yíbàn, half — note the tone change on 一 to "yí"), 半天 (bàntiān, half a day / quite a while), 半夜 (bànyè, midnight / "half of the night"), 半价 (bànjià, half price), 多半 (duōbàn, mostly / probably). The "in the middle of doing something" sense: 半路 (bànlù, halfway), 半途而废 (bàntú érfèi, "give up halfway" — common idiom for leaving something unfinished).

Japanese: on-reading ハン (han) is dominant — 半分 (hanbun, half), 半年 (hantoshi, half a year), 三時半 (sanji-han, half past three — every Japanese time-telling lesson uses this), 半数 (hansū, half the number / majority threshold), 過半 (kahan, majority — "more than half"), 後半 (kōhan, latter half — used in sports broadcasting). Kun-reading なかば (nakaba) — 二十代なかば (nijūdai nakaba, mid-twenties), 半ば (nakaba, midway / halfway).

The Korean Peninsula 韓半島 (Hanbando / Han Bàndǎo / Kankokuhantō / 한반도) uses 半島 to describe the geographic peninsula — "half-island", a terrain that's half land and half surrounded by sea.

Memory aid: a cow split in half — the original image of bisection.