fifty

number (plural fifties)

• the number equivalent to the product of five and ten; half of one hundred; 50:only fifty per cent of the aircraft were serviceable about fifty of us filed in a fifty-pound salmon (Roman numeral: l or L)
• (fifties) the numbers from 50 to 59, especially the years of a century or of a person’s life:Elvis is the icon of the Fifties
• fifty years old:she looked about fifty
• fifty miles an hour:I was doing about fifty
• a size of garment or other merchandise denoted by fifty.
• a fifty-pound note or fifty-dollar bill.