根
gēn · HSK 4
root
🌳 根 = 木 (tree) + 艮 (stopping/firm) — the firm part of a tree, its root
Used as a measure word for long, thin things like hairs, threads, ropes, bones, or cigarettes. Core sense is root, so it extends to anything rootlike or stick-shaped. Sounds like the English name Ken with a flat first tone.
根 — tree radical 木 + 艮 (phonetic)
根 is a semantic-phonetic compound. The left side 木 ('tree') gives the meaning, since the character originally referred to the roots of a tree. The right side 艮 supplies the sound. From 'tree root' it extended to mean 'root, base, foundation' in general.