From ọ̀- + kị̀ka, the root ka can be found in other terms for finger, see Doublet of ìka, Doublet of ùka, proposed to be derived from Proto-Yoruba *ʊ̀-ka. Perhaps potentially from the same root as èjìká and aká, which can be traced back to Proto-Niger-Congo *-ka (“hand, five”), however the tonal differences of the "a" make this unclear. If not, it is likely a Doublet of ẹ̀ka (branch), suggesting a derivation from a root meaning "to be divided," to be "branched out."