- umbra (n.)
[umbra 词源字典]
- 1590s, "phantom, ghost," a figurative use from Latin umbra "shade, shadow" (see umbrage). Astronomical sense of "shadow cast by the earth or moon during an eclipse" is first recorded 1670s. Meaning "an uninvited guest accompanying an invited one" is from 1690s in English, from a secondary sense among the Romans. Related: Umbral.[umbra etymology, umbra origin, 英语词源]