tertiary
1 adj Tertiary means third in order, third in importance, or at a third stage of development.
FORMAL He must have come to know those philosophers through secondary or tertiary sources.
2 adj Tertiary education is education at university or college level. (BRIT) ADJ n ...institutions of tertiary education. in AM, use higher education
tertiary sector (tertiary sectors plural )The tertiary sector consists of industries which provide a service, such as transport and finance. (BUSINESS) n-count
...economies that are slowly increasing the proportion of their labour force in the tertiary sector.