HCF or highest common factor is a term commonly used in mathematics. It refers to the largest factor of two or more integers that are common. While HCF is the most common term used, there are synonyms that can be used interchangeably, such as greatest common divisor (GCD) and highest common divisor. Additionally, it can also be referred to as the greatest common measure or highest common factor of two numbers. These synonyms are often used in different parts of the world or in different math textbooks. Nevertheless, they all point to the same concept-the greatest factor that divides two or more numbers.