One of the portions of a volatile liquid within certain boiling point ranges, such as petroleum naphtha fractions or gas-oil fractions.

An expression which is the product of a real number or complex number with the multiplicative inverse of a real or complex number.

In powder metallurgy, that portion of sample that lies between two stated particle sizes. Also known as cut.

A portion of a mixture which represents a discrete unit and can be isolated from the whole system.