Illustrated Glossary of Organic Chemistry

Absolute configuration: The spatial position of atoms or groups (i.e, the configuration) around a stereocenter, as determined by the Cahn-Ingold-Prelog rules, and designated as R or S.

Cahn-Ingold-Prelog priorities: HO > CH3CH2 > CH3 > H, so this is (R)-2-butanol. This is an example of absolute configuration; the configuration is not relative to some other group with in the molecule.