From taba'; properly, a seal (as sunk into the wax), i.e. Signet (for sealing); hence (generally) a ring of any kind -- ring.
see HEBREW taba'
H2885. tabbaath
טַבַּ֫עַת noun feminine signet, signet-ring, ring (on formation see LagBN 88; Assyrian ‰imbu°u, seal-ring, Muss-Arnl.c.) — absolute טַבַּעַת Exodus 26:24 3t.; construct id. Esther 3:12 3t.; טַבַּעְתּוֺ Genesis 41:42 2t.; plural absolute טַבָּעוֺת Isaiah 3:1; Exodus 28:23; טַבָּעֹת 25:12 (twice in verse) + 14 t. construct טַבְּעוֺת 28:23 2t.; טַבְּעֹת 25:12 12t.; suffix טַבְּעֹתָ֯ו 28:28; 39:21; טַבְּעֹתֵיהֶם 26:29; טַבְּעֹתָם 36:34; —
1 signet-ring, of king, taken from his hand and given as token of authority Genesis 41:42 (E), Esther 3:10; 8:2; used in sealing official missives 3:12; 8:8 (twice in verse); 8:10 (verb חָתַם).
2 ring, as ornament Isaiah 3:21; as gift for sacred purposed Exodus 35:22; Numbers 31:50 (both P).
3 most often (only in Exodus) of rings for staves of ark, for curtains, for ephod, and other sacred furniture Exodus 25:12 (3 t. in verse) + 35 t. in Exodus (all P).