Correct spelling

23rd

Correct spelling, explanation: this is the correct form of this ordinal number because the word form is twenty-third. The ending of the word form of an ordinal number is always the ending of its numeral form. Therefore twenty-third is 23rd (not 23th), sixty-seventh is 67th, etc. This shows why 23rd is the correct form.

Definition of 23rd:
numeral, the ordinal number between 22nd and 24th
He was 23rd in the national competition of speed reading.
It was the 23rd anniversary of our school funding yesterday. We had a nice celebration with the teachers and parents.


Incorrect spelling

23th

Incorrect spelling, explanation: 23th is incorrect because th is not the ending of the word from twenty-third. Although rd is, so 23rd is correct. This is a general rule for all ordinal numbers (for example first is 1st, sixth is 6th). This is why 23rd is the correct form.

Incorrect spelling

23nd

Incorrect spelling

Incorrect spelling

23st

Incorrect spelling