月晕, 发黄(熔块瓷缺陷)

Moon \Moon\, v. t. [imp. & p. p. {Mooned}; p. pr. & vb. n.
{Mooning}.]
1. To expose to the rays of the moon.

If they have it to be exceeding white indeed, they
seethe it yet once more, after it hath been thus
sunned and mooned. --Holland.

2. To expose one's naked buttocks to (a person); -- a vulgar
sign of contempt or disrespect, sometimes done as a prank.
[PJC]