(Heb. mitsnepheth), something rolled round the head; the turban or head-dress of the high priest (Exodus 28:4,37,39; 29:6, etc.). In the Authorized Version of Ezekiel 21:26, this Hebrew word is rendered "diadem," but in the Revised Version, "mitre." It was a twisted band of fine linen, 8 yards in length, coiled into the form of a cap, and worn on official occasions (Leviticus 8:9; 16:4; Zechariah 3:5). On the front of it was a golden plate with the inscription, "Holiness to the Lord." The mitsnepheth differed from the mitre or head-dress (migba'ah) of the common priest. (See BONNET .)
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Mitre'". "Easton's Bible Dictionary".