Arithmetical proportion, also known as arithmetic progression, is a mathematical concept used to describe a series of numbers with a constant difference between each term. Synonyms for arithmetical proportion include linear progression, arithmetic sequence, and arithmetic series. In a linear progression, each subsequent number is a constant increment or decrement away from the previous number. An arithmetic sequence describes a pattern of numbers where the difference between consecutive terms is the same. An arithmetic series refers to the sum of an arithmetic sequence. These synonyms are often used interchangeably and can help clarify the meaning of arithmetical proportion in various mathematical contexts.