facula

名词 facula:

1. a bright spot on a planet
2. a large bright spot on the sun's photosphere occurring most frequently in the vicinity of sunspots

fac.u.la

n.（名词）
【复数】 fac.u.lae[-lô.]
Any of various large, bright spots or veined patches on the sun`s photosphere, usually near sunspots.
光斑：太阳光球上大的亮点或有脉纹的亮区，通常靠近黑子处

来源：
Latin [small torch]
拉丁语 [小火把]
diminutive of fax fac- [torch]
fax的小后缀 fac- [火炬]