The crossword solution for the term 'ONE OF THREE EQUAL PARTS' is 'THIRD', which has 5 letters. The term 'ONE OF THREE EQUAL PARTS' refers to a fraction, which is a number that can be expressed as the quotient of two integers. A fraction is made up of three parts: the numerator, the denominator, and the fraction itself. The numerator is the number above the line, the denominator is the number below the line, and the fraction itself is the result of dividing the numerator by the denominator. In this case, the fraction is 1/3, and the THIRD part of the fraction is the 'THIRD'.