Other forms: thirds
Third is the ordinal for three — third place, the third of March, one third of the total. It is written 3rd, and the rd is what makes it look right.
As a fraction it means one of three equal parts, and there the plural is regular: two thirds, three thirds. Note that the ordinal takes the with a noun — the third house — and drops it in dates spoken aloud in American English. Two useful compounds: third party means somebody not directly involved, which matters in insurance and contracts, and the third degree means intensive questioning. And third-rate means poor quality, on a scale where nobody ever says second-rate approvingly either.
1adjectivecomingComing after the second.~92%
“It is the third house on the left.”
2nounthirdOne of three equal parts.~6%
“Cut it into thirds and share it out.”
3noungearThe third gear of a vehicle.~2%
“Change into third before the hill.”
Shares are an estimate: a language model read 17 sentences found in the wild and placed 16 of them on a sense (1 were unclear) — a count of our sample, not a measurement of English.
third is an ordinal number.
Old English thridda kept the r before the vowel — thrid, matching three. English later swapped the two sounds round, which is called metathesis and is the same thing that turned brid into bird. Third is three with its letters shuffled.
Proto-Indo-European
*tréyes
Proto-Indo-European
*tr̥tyós
Proto-Germanic
*þridjô
Old English
þridda
Middle English
thirde
English, today
third
From Middle English thirde, thridde, from Old English þridda, from Proto-Germanic þridjô, from Pre-Germanic tretyós, a remodeling of Proto-Indo-European tr̥tyós.
Etymology from Wiktionary, CC BY-SA