BUR #27590 has been approved by @nonamethanks.
The protruding part of the face below the mouth, formed by the apex of the lower jaw. This tag should be used when particular emphasis is on the chin.
It should surprise nobody that this wiki has been completely ignored, resulting in the chin tag falling to the same level of uselessness as the now defunct hands and eyes tags. I looked over the first ten pages of the tag, and I could count on one hand the amount that had even somewhat notable chins - it's pure padding. It also gets in the way of much more important tags in the autocomplete, showing up before chinese_commentary or china_dress when you just type "chin".