1
- third in order or level第三的; 第三位的; 第三级的：
most of the enterprises were of tertiary importance
大部分企业属三级企业
the tertiary stage of the disease.
疾病的第三阶段。
1.1
- chiefly Brit. relating to or denoting education at a level beyond that provided by schools, especially that provided by a college or university〈主英〉（继初等、中等教育之后的）职业教育的; 高等教育的, 大学教育的。
1.2
- relating to or denoting the medical treatment provided at a specialist institution第三期治疗的。
2
Tertiary
Geology of, relating to, or denoting the first period of the Cenozoic era, between the Cretaceous and Quaternary periods, and comprising the Palaeogene and Neogene sub-periods【地质】第三纪（或系）的。
3
- Chemistry (of an organic compound) having its functional group located on a carbon atom which is itself bonded to three other carbon atoms【化】叔的; 特的。
3.1
- Chemistry (chiefly of amines) derived from ammonia by replacement of three hydrogen atoms by organic groups【化】（尤指胺）叔的; 三代的。
1
the Tertiary
Geology the Tertiary period or the system of rocks deposited during it【地质】第三纪; 第三系; 第三纪岩。- The Tertiary lasted from about 65 to 1.6 million years ago. The mammals diversified following the demise of the dinosaurs and became dominant, as did the flowering plants.
2
- a lay associate of certain Christian monastic organizations第三修道会会员（某些基督教组织做杂务的会支）：
a Franciscan tertiary.
方济各会的会员。
词源
mid 16th cent. (in sense 2 of the noun)： from Latin tertiarius 'of the third part or rank'， from tertius 'third'.