染まる
そまる · somaru · JLPT N1 · verb-godan
to be dyed
🎨 染まる = 染 (dye) + まる (become): to become dyed
染 is the kanji for dye, read some here. まる marks becoming a state, as in 決まる (to be decided). 染める (someru) is the active verb, to dye something; 染まる is the passive, to become dyed.
染 — water 氵 + nine 九 + wood 木
染 depicts the dyeing process: 氵 (water) for the dye liquid, 木 (wood) for plant-based dyestuffs, and 九 (nine) suggesting repeated dippings to deepen the color. Originally meaning 'to dye cloth,' it later extended to figurative senses like 'to be influenced' or 'to contract' (as in illness).