[ 'tə:ʃ(ə)ri ]
■ adjective
1》 third in order or level.
↘ chiefly Brit. relating to or denoting education at a level beyond that provided by schools.
2》 relating to or denoting medical treatment provided at a specialist institution.
3》 ( Tertiary ) Geology relating to or denoting the first period of the Cenozoic era (between the Cretaceous and Quaternary periods, about 65 to 1.64 million years ago).
4》 Chemistry (of an organic compound) having its functional group on a carbon atom bonded to three other carbon atoms.
↘ Chemistry derived from ammonia by replacement of three hydrogen atoms by organic groups.
■ noun a lay associate of certain Christian monastic organizations.
Origin
C16: from L. tertiarius 'of the third part or rank'.