noun, noun which may take the genitive case particle 'no'
two legs; two feet
Used for counting limbs or feet of living creatures, or for bipedal things.
Humans walk on two legs.
They are developing a bipedal robot.
この店では二足目が半額になる。
At this store, the second pair is half price.
One pair of footwear; 二足 is two pairs.
Literally 'two legs', but more colloquial and often used for animals or objects standing on two legs.
Standard kanji spelling for counting legs, feet, or pairs of footwear.
Numerical variant; common in informal or space-constrained writing.
Compound of 二 (two) and the counter 足 (そく) for pairs of footwear or legs. The reading にそく is standard.