芽
yá · HSK 7
sprout
🌱 grass radical 艹 over 牙 (tooth, also yá) = the phonetic tooth tells you the sound, grass tells you a sprout
芽 stacks the grass radical 艹 on top of 牙 (yá, tooth). 牙 is purely the sound clue, so the reading yá matches tooth exactly; the grass on top narrows the meaning to a new green sprout or bud.
芽 — grass radical 艹 + tooth 牙 (phonetic)
芽 is a semantic-phonetic compound. The grass radical 艹 on top signals plants, while 牙 ('tooth') below provides the sound 'ya'. The original sense is the tender sprout or shoot pushing up from a seed, like a small tooth emerging from the soil.