木 is a single tree drawn whole — two branches reaching up, two roots reaching down, the trunk down the middle. The most beginner-friendly demonstration of how the script builds: stack two trees and you get 林 (lín, woods); three trees become 森 (sēn, dense forest). Identical across 繁體 / 新字体 / 简体.

As a radical, 木 marks anything wood-related: 板 (board), 桜 / 櫻 (cherry tree), 椅 (chair), 棚 (shelf), 校 (school — historically wood-built), 林 (woods), 森 (forest). Spotting 木 on the left or bottom of a character is one of the cheapest reading shortcuts available.

Mandarin: mù, falling 4th tone. 树木 (shùmù, trees), 木头 (mùtou, wood/timber), 木瓜 (mùguā, papaya — "wood melon"), 木乃伊 (mùnǎiyī, mummy — phonetic loan from English). Note that everyday "tree" is 树 (shù) in Mandarin; 木 alone means the material more often than the living plant.

Japanese: two on-readings split by register — モク (moku) in 木曜日 (mokuyōbi, Thursday) and 木材 (mokuzai, lumber); ボク (boku) in 大木 (taiboku, large tree). The kun-reading き (ki) is the everyday word — 木 (ki, tree), 木の葉 (konoha, leaves), 木造 (mokuzō, wooden construction). Thursday in the planetary week is "wood day" (Jupiter, the wood planet).

Memory aid: trunk + two arms + two legs = a tree standing on the page. If a compound has 木 in it, expect wood, plant, or anything carved from a tree.