counter for chairs or seats
Used to count chairs, seats, and similar items with legs. Not a general counter for furniture.
There are four chairs in this room.
Refers to the foot or leg, often in a more formal or technical context compared to あし. Commonly used in compound words.
There are thirty chairs in the classroom.
The legs of this desk are made of metal.
He sat with his legs crossed.
That model has long legs.
足 is the everyday word for foot or leg, while 脚 is a more formal or technical term used especially in compounds and as a counter for chairs.
客 (guest, customer) shares the same reading きゃく with 脚 but is a completely different word meaning a visitor, not a leg or counter.
足 broadly covers the foot or the whole leg, while 脚 (also read あし) narrows to the leg itself—often from hip to foot—and is also used for furniture legs and the lower part of a kanji.
Standard kanji spelling for the counter and noun senses.
The kanji 脚 originally depicts a leg and is used in Chinese-derived compounds. The reading きゃく is the on'yomi.