Of fourth rank or order / Of a mathematical expression containing e.g. x⁴ / Relating to or in number base four / (organic chemistry) quaternary ammonium / (inorganic chemistry) composed of four elements

(chemistry) A quaternary compound. / (geology) The Quaternary period or the system of deposits laid down during it.

(geology) The geological period of the Cenozoic Era immediately following the Tertiary. It is subdivided into the Pleistocene and the Holocene Epochs.

plural of quaternary

The number ten.

(biochemistry, molecular biology) The arrangement of multiple folded or coiled proteins to form a multi-subunit complex.

(chemistry) An ammonium group in which each hydrogen has been replaced by an alkyl or aryl group

The sector of industry that involves the intellectual services: research, development, and information. It is considered the fourth basic industry.

Synonym of quaternary care

(medicine) Highly specialized healthcare treatments, such as experimental medicine and uncommon surgical procedures.