forty-third adjective 1noun 1forms 1 adjective1 •The ordinal form of the number forty-three, describing a person or thing in position number 43 of a sequence.The answer appears on the forty-third page of the book.She finished forty-third in the race. noun1 •One of forty-three equal parts of a whole.A forty-third of 860 is 20. formsforty-thirds
