seventy-oneth /ˌsɛvənti ˈwʌnθ/adjective 1noun 1forms 1 adjective1 •(nonstandard) seventy-first noun1 •(nonstandard) seventy-first (a fractional part of seventy-one)he found ... that the circumference was three times the diameter plus a quantity which was less than a seventh but more than ten seventy-oneᵗʰˢ. — 1892 formsseventy-oneths
