40 (forty) is the natural number following 39 and preceding 41.Despite being related to the word "four" (4), 40 is spelled "forty" in the American English dictionary, and "fourty" in the Oxford English Dictionary. The reason Americans spell it as "forty" is that etymologically (also in accents without the horse–hoarse merger) the words have different vowels.[citation needed] "Forty" contains a contraction in the same way that "fifty" contains a contraction of "five".[citation needed]