twenty-oneth /ˌtwɛnti ˈwʌnθ/adjective 1noun 1forms 1 adjective1 •(nonstandard) twenty-first noun1 •(nonstandard) A fractional part of twenty-one, a twenty-firstaverage ministerial age of pastors 22 years and nineteen twenty-oneths; average pastoral age, 13 years and ten twenty-oneths — 1844 formstwenty-oneths
