umbra

Umbra, umbrae, f., first declension. Shadow and shade in both English senses, the dark shape a thing casts and the cool place under it, and then the sense that matters most in literature: the shade of a dead person. Virgil's underworld is populated by umbrae, and the word does duty for the whole ghostly population.

Two smaller uses are worth knowing. At a Roman dinner an umbra was an uninvited guest brought along in the train of an invited one, which is a very exact piece of social vocabulary. And umbra can mean a mere semblance, the appearance without the substance - umbra libertatis, the shadow of freedom. Umbraculum, "a sunshade", gives Italian ombrello and English umbrella; umbrage and adumbrate come from the same word.