From the same as buwts; an egg (from its whiteness) -- egg.
see HEBREW buwts
H1000. betsah
[בֵּיצָה] noun feminineIsaiah 10:14 egg (Late Hebrew id., Arabic , Aramaic בִּיעֲתָא, ) — only Plural בֵּיצִים Deuteronomy 22:6 (twice in verse); Isaiah 10:14; construct בֵּיצֵי 59:5; suffix בֵּיצֶיהָ Job 39:14, בֵּיצֵיהֶם Isaiah 59:5; — eggs 10:14 (of small bird צפור) Deuteronomy 22:6 (twice in verse), compare Isaiah 10:14 (in simil.); (of ostrich רננים) Job 39:14; (of great viper צפעוני) Isaiah 59:5 (twice in verse) (metaphor)