ソク, あし, た.りる, た.る, た.す, あ, あす, おす, たらし
leg, foot, be sufficient, counter for pairs of footwear
JLPT4 G1 S7 F343
A depiction of a *leg*/*foot*. Conceptually, the Old Chinese term attached to 足 would have involved compression or compaction (compare the cognate 束), for instance, in compacting an object by stamping or trampling it → *sufficient*; *ample* (← compact sufficiently/amply for the purpose) → *serve a purpose*. Also, *add*/*supplement* (← add material to that being compacted) → *compensate* (for); *aid*.
[Full Kanji Etymology List]