What does kaya mean in hopi?

The idea that the Word kaya means an older (or eldest) sister is totally false, originating with a published work of popular fiction which includes many invented elements. Writers of Children's Books are not normally experts in native American culture or language, so all such books should be treated with extreme caution.

The genuine Hopi Word for an older sister is qööqa, which transforms to kaaka in direct address. A younger sister is siwa.

There is no kaya in the Hopi language.