כֶּתֶרkether

crown (Esther 1:11; Esther 2:17; Esther 6:8)

Pronunciation: keh'-ther · Hebrew/Aramaic (Old Testament) · H3804

Same root

כָּתַרkâthar · H3803to enclose; hence (in a friendly sense) to crown, (in a hostile one) to besiege; also to wait (as restraining oneself)

Where it appears

Appears 3 times in the Bible.

Esther 1:11 to bring Queen Vashti to him with the royal crown on her head. He wanted the nobles and all the other men to gaze on her beauty, for she was a very beautiful woman.
Esther 2:17 And the king loved Esther more than any of the other young women. He was so delighted with her that he set the royal crown on her head and declared her queen instead of Vashti.
Esther 6:8 he should bring out one of the king’s own royal robes, as well as a horse that the king himself has ridden—one with a royal emblem on its head.

Source: Brown, Driver and Briggs, Hebrew and English Lexicon of the Old Testament (1906), public domain; markup by unfoldingWord, CC BY (github.com/unfoldingWord/Brown-Driver-Briggs-Enhanced).