say it: sib
sib is a noun meaning "a person's brother or sister". It carries 2 recorded senses.
a person's brother or sister
one related by blood or origin; especially on sharing an ancestor with another
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for sib come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.