Chiefly used in old religious texts; in later texts the synonym jꜣbtt is usually used instead. As the two words share several written forms, the context of time period and linguistic register may sometimes be the only means to determine which reading is meant.
The Wörterbuch considers this a further derived nominalized nisba adjective, presumably formed from jꜣbt(“east”) + -(j)(nisba ending); however, the form *jꜣbtj with the nisba ending written out is nowhere attested with this meaning. Such an analysis is, nonetheless, supported by the masculine gender of this term.
James P[eter] Allen (2010) Middle Egyptian: An Introduction to the Language and Culture of Hieroglyphs, 2nd edition, Cambridge: Cambridge University Press, →ISBN, page 389.
