# Algorithm definition

ălgə-rĭthəm
Frequency:
A finite set of unambiguous instructions performed in a prescribed sequence to achieve a goal, especially a mathematical rule or procedure used to compute a desired result. Algorithms are the basis for most computer programming.
The definition of an algorithm is a specific and logical procedure to be followed in order to achieve specific results, or to solve a math problem.

An example of a very basic algorithm is the procedure in math that dictates how to add double (or more) digit numbers together in order to achieve the correct answer.

An example of an algorithm is the process that Google uses in its search engine to ensure high quality informational results when the user enters search terms.

noun
A finite set of unambiguous instructions that, given some set of initial conditions, can be performed in a prescribed sequence to achieve a certain goal and that has a recognizable set of end conditions.
noun
A set of rules and procedures for resolving a mathematical and/or logical problem, much as a recipe in a cookbook helps baffled cooks in the kitchen resolve meal problems. A computer program can be viewed as an elaborate algorithm, and in computer science, an algorithm usually indicates a mathematical procedure for solving a recurrent problem. The word algorithm is believed to stem from the name of a mathematician at the Royal Court in Baghdad, Mohammed ibn-Musa al-Khwarizmi (780–850 a.c.). Today, information security professionals in particular are concerned with cryptographic ­algorithms—those used to encrypt, or encode, messages. Different algorithms have different levels of complexity, which is related to key size. For example, a 41-bit key is twice as hard to crack, or decode, as a 40-bit key. A 128-bit key is a trillion times harder to crack than a 40-bit key. Graham, R. Hacking Lexicon. [Online, 2001.] Robert Graham’s Website. http://www.linuxsecurity.com/resource_files/documentation/hacking-dict.html; TechTarget. SearchVB.com Definitions: Algorithm. [Online, July 6, 2004.] TechTarget Website. http:// searchvb.techtarget.com/sDefinition/0,,sid8_gci211545,00.html.
A precise step-by-step plan for a computational procedure that possibly begins with an input value and yields an output value in a finite number of steps.
noun
A logical, systematic, step-by-step procedure for solving a mathematical problem.
(comput.) A predetermined set of instructions for solving a specific problem in a limited number of steps.
noun
(archaic) Calculation with Arabic numerals; algorism.
noun
Any systematic method of solving a certain kind of problem.
noun
The repetitive calculations used in finding the greatest common divisor of two numbers.
noun

Singular:
algorithm
Plural:
algorithms

## Origin of algorithm

• Variant (probably influenced by arithmetic) of algorism

### From American Heritage Dictionary of the English Language, 5th Edition

• From French algorithme; from the Old French algorisme (“the Arabic numeral system”), a modification likely due to a mistaken connection with Ancient Greek ἀριθμός (arithmos); from Medieval Latin algorismus, a transliteration of Arabicized form of the name of the Persian mathematician al-Khwārizmī (الخوارزمي (“native of Khwarezm”)).