1third 
/ˈθɚd/ adjective
always used before a noun /ˈθɚd/ adjective 1 a : occupying the number three position in a series
▪ We sat in the third row. ▪ the third house on the left ▪ the author's third novel ▪ C is the third letter in the alphabet. ▪ That's the third time I've seen him today. ▪ The office is on the third floor.
b : next to the second in importance or rank
▪ I won third prize. ▪ Do you have a third choice? 2 : equal in size, value, amount, etc., to one third of something
▪ a third share in the profits ▪ a third pound of cheese 3 : used to refer to the third forward gear or speed of a vehicle
▪ shift into third gear
▪ We sat in the third row. ▪ the third house on the left ▪ the author's third novel ▪ C is the third letter in the alphabet. ▪ That's the third time I've seen him today. ▪ The office is on the third floor.
b : next to the second in importance or rank
▪ I won third prize. ▪ Do you have a third choice?
▪ a third share in the profits ▪ a third pound of cheese
▪ shift into third gear
the third time is the charm (US) or Brit third time lucky
— used to say that two efforts at something have already failed but perhaps the third will be successful
— third adverb
▪ She finished third in the race. ▪ the third highest mountain
▪ She finished third in the race. ▪ the third highest mountain
