Oldest stratum Synonyms

OS abbreviation

OS is an abbreviation for Oldest Stratum

What does OS stand for?

OS stands for "Oldest Stratum"

(noun) one of the segments of society into which people are grouped
(noun) the placement of someone or something in relation to others in a vertical arrangement
(noun) one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock)