Unknown. The once-popular derivation from
Egyptian(bw,
“place, thing, -ness”) is untenable given the form of the Fayyumic descendant.
[1] A corresponding hieroglyphic Egyptian word
(mꜣꜥ,
“place”) is attested from the end of the Third Intermediate Period onward, especially in late temple inscriptions, with the earliest certain attestation being in Papyrus Brooklyn 47.218.84,
[2] but this is contemporaneous with the spread of early Demotic. Meeks proposes that another term
bpꜣt attested at the beginning of the Ramesside Period might be an early writing of the same word, but the absence of the final ayin is problematic.
[2]