The word "fifty" has a few synonyms that you can use to refer to the same number. One of the synonyms for "fifty" is "half a hundred," which is commonly used in informal settings. Another synonym that you might come across is "quinquagenarian," which refers to a person who is in their fifties. You can also use "five tens" to refer to a set of 50 items, such as banknotes. "L" is another synonym for 50, as it is the Roman numeral representation of this number. Finally, you can use "pentagenary" to refer to a period of 50 years, such as an anniversary.