Correct spelling

72nd

Correct spelling, explanation: 72nd is the correct form, because second at the end uses ending nd to show ordinal form of the number. Therefore seventy-second is written as 72nd, not 72th. Th ending is used for ordinal numbers which end with th sound.

Definition of 72nd:
numeral, ordinal number between 71st and 73rd
My grandpa had his 72nd birthday last week, but he’s living his best life and wants to travel around South America next year.
I wanted to sign up for this lecture, but I don’t think I will get in. I am 72nd on the waiting list.


Incorrect spelling

72th

Incorrect spelling, explanation: this form is incorrect, because th is used with ordinal numbers ending with such sound, for example seventeenth or fifty-ninth. Seventy-second (72nd), however, ends with nd, so this is the suffix for numeral form. Therefore 72nd is correct and 72th is an incorrect form.

Incorrect spelling

72st

Incorrect spelling

Incorrect spelling

72rd

Incorrect spelling