Two-thirds is an expression that represents a fractional amount equal to two parts out of a total of three. There are several other ways to express this same concept, such as "66.67%," "0.67," or "2/3rds." Additionally, words that can be used as synonyms for two-thirds include the phrases "majority," "plurality," "double the amount of," or simply "much more than half." This term can be used to represent a share of anything that can be divided into three equal parts, such as food, time, or money, and is a useful way to express a concept that is not easily quantified otherwise.