八 is simple ideogram, which resembles an object which is divided into two halves. The character originally meant “separate”, a meaning now replaced by 分. 八 has been phonetically loaned for the number eight.
八 can serve as a semantic component to form characters.
Characters formed by the semantic component 八
公, 分 gōng, fēn
八 also can serve as a phonetic component to form characters.
Characters formed by the phonetic component 八
扒, 叭, 仈, 朳, 玐, 釟 bā bā bā bā bā bā
趴 pā
汃 pā/pà/bīn
See also another 八, a variant of 手.