Exodus 16:36

עשירית האפה [THE OMER] IS THE TENTH PART OF AN EPHAH — The Ephah is three Seahs, and the Seah is six Kabs, and the Kab is four Logs and the Log has the capacity of six eggs: it follows, therefore, that the tenth of an Ephah has the capacity of forty-three and a fifth eggs — and this is the minimum quantity of dough for the Challa (the minimum quantity to which applies the injunction to separate a portion of the dough; cf. Numbers 15:20), and the measure for the meal offering (cf. Rashi on Eruvin 83b).

וְהָעֹ֕מֶר עֲשִׂרִ֥ית הָאֵיפָ֖ה הֽוּא׃ {פ}

Now an ῾omer is the tenth part of an efa.