Tertiary
/ˈtɜːr.ʃi.ə.ri/noun
Relating to the third level, order, stage, or degree.
Did you know?Tertiary ultimately descends from the same ancient numeral root as three, triad, and trident, linking an academic classification term to the oldest Indo-European way of counting threefold power.
Etymological Timeline
Proto-Indo-European
PIE
*tréyes
“Three”
Ancient Greek
Greek
treîs
“Three”
Classical Latin
Latin
tertius
“Third; the third in sequence”
Late Latin
Latin
tertiarius
“Of or belonging to the third”
15th Century
Middle English
tertiarie
“Third in order or rank”
Modern English
English
tertiary
“Third-level, third-order, or relating to a third stage”