means A word for a family member by blood or marriage, or an adjective meaning that something is judged in comparison to something else rather than on its own absolute terms.

from From Latin 'relativus,' meaning 'having reference or relation,' built from 'relatus,' the past participle of 'referre' — 'to carry back, refer.' That verb breaks into 're-' ('back') plus 'ferre' ('to carry'), so a relative is literally something 'carried back' to a point of comparison. The kinship sense and the comparative sense both grow from the same idea: a relative is defined by how it stands in relation to something else. It came into English through Old French in the late Middle Ages, and 'relativity' as a scientific term only acquired its famous Einsteinian weight in the early 20th century.