algorithm

The current term of choice for a problem-solving procedure, algorithm, is commonly used nowadays for the set of rules a machine (and especially a computer) follows to achieve a particular goal. It does not always apply to computer-mediated activity, however. The term may as accurately be used of the steps followed in making a pizza or solving a Rubik’s Cube as for computer-powered data analysis.

Algorithm is often paired with words specifying the activity for which a set of rules have been designed. A search algorithm, for example, is a procedure that determines what kind of information is retrieved from a large mass of data. An encryption algorithm is a set of rules by which information or messages are encoded so that unauthorized persons cannot read them.

Though first attested in the early 20th century (and, until recently, used strictly as a term of mathematics and computing), algorithm has a surprisingly deep history. It was formed from algorism “the system of Arabic numerals,” a word that goes back to Middle English and ultimately stems from the name of a 9th-century Persian mathematician, abu-Jaʽfar Mohammed ibn-Mūsa al-Khuwārizmi, who did important work in the fields of algebra and numeric systems.