a group of plants or animals that is a surviving remnant of an otherwise extinct form
archaic a widow
a geological or geographical feature, e.g. a lake or mountain, or a rock remaining after other parts have disappeared or substantially altered
archaic = widow1
His landlady, Mrs Bardell – the relict and sole executrix of a deceased custom-house officer – was a comely woman of bustling manners and agreeable appearance — Dickens
[(sense 1 and 2) from relict (adj) residual, from Latin relictus, past part. of relinquere: see relinquish; (sense 3) early French relicte (woman) left behind, from late Latin relicta, fem of relictus]