Initialism of on behalf of.

(linguistics) Initialism of Oxford English Dictionary.

plural of the letter o

plural of O

A subject-based qualification superseded in England by GCSEs, but still available as an international examination.

(Indo-European linguistics) In Proto-Indo-European linguistics, an ablaut form of a Proto-Indo-European root, characterised by the presence of the */o/ vowel phoneme in place of */e/.

A yellow diarylmethane dye used as a fluorescent stain.

(slang) Oxygen. / (slang) Orgasms.

(linguistics) A word, especially a noun in Indo-European linguistics, whose stem ends in /o/.

plural of o-stem