a fine headdress: the decorative head covering worn by a serving priest, a bridegroom, or a woman in her finery, and kept on or laid aside as a public sign of joy or grief.
This word names a thing you can put on and take off: cloth or a band wrapped around the head to make the wearer look splendid. It belongs to the same family as the verb for making something beautiful (פָּאַר) and the abstract noun for splendor itself (תִּפְאֶרֶת), so the object and the beauty it shows off share one root. Israel had other head coverings with other jobs, and this one is the handsome, festive piece rather than a badge of rank: the high priest's own turban (מִצְנֶפֶת) is a different word, and a metal circlet (עֲטָרָה) is different again.
Because the thing is worn on formal and glad occasions, it does two jobs at once. It marks a person's place, as with the linen headwear of the ordinary priests on duty, in the wilderness tent and again in Ezekiel's vision of a restored temple. And it marks the mood of a day: a bridegroom puts one on for his wedding, and a woman wears one along with her bracelets and rings.
That second job is why the word turns up in the middle of grief. Mourners in Israel bared their heads or heaped dust on them, so a headdress left bound in place is a visible announcement that a person is not mourning. Ezekiel is told to keep his on the day his wife dies, and the exiles are warned they will do the same when Jerusalem falls, too stunned for the usual rites. Isaiah turns it the other way: God gives the mourners of Zion a headdress in place of the ashes on their heads, and in Hebrew the word for the headdress and the word for ashes sound almost the same.