specular (adj.)youdaoicibaDictYouDict[specular 词源字典]
1570s, "reflective" (like a mirror), from Latin specularis, from speculum "a mirror" (see speculum). Meaning "assisting in vision; affording a view" is from 1650s, from Latin speculari "to spy" (see speculation).[specular etymology, specular origin, 英语词源]