means The people who share at least one of your parents — your brothers and sisters, collectively.

from From Old English 'sibling,' meaning a relative or kinsman, built on 'sibb' — kinship, peace, the bonds of family — plus the diminutive '-ling.' The word nearly vanished from English for centuries, then was revived in the early 20th century by anthropologists and geneticists who needed a tidy, gender-neutral term for 'brothers and sisters.' So the cozy old root for kinship came back wearing a lab coat. That ancient 'sibb' also survives in the name Sibyl-adjacent forms and, more clearly, in 'gossip' — once 'godsibb,' a godparent, a relation by spirit rather than blood.