lexicow

algorithm

/ˈælɡəˌrɪðəm//ˈælɡərɪðəm/·noun
A token drops in from the top and meets a small diamond with a question mark inside — the fork where everything is decided. The first one answers yes, and the left branch lights up and carries it down to one box; the next answers no, and the right branch lights instead, sending it to a different box entirely. Same entrance, same question, two clean outcomes — and which one you get depends only on the answer. Watching it run, I see there is no guesswork anywhere: every case is sorted by a fixed rule, yes here, no there, the same way every time.
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Definition

An algorithm is a finite sequence of exact, ordered steps that turns an input into a result: do this, then this, then stop. The name is a worn-down tribute to the 9th-century mathematician al-Khwārizmī, whose rules for calculation reached medieval Europe as 'algorism'. What defines an algorithm is not cleverness but repeatability — follow the same steps in the same order and you reach the same answer every time. A recipe, a long-division method, and the strategy a search engine uses to rank pages are all algorithms. It is constantly confused with logarithm, a word that merely sounds alike.

Examples

  • The recommendation algorithm ranks each clip against one hidden parameter after another, by rules the company keeps secret.
  • Engineers spent months trying to calibrate the algorithm so it stopped favouring the loudest posts.
  • A good algorithm barely slows down even when the volume of data begins to surge.

Collocations

a sorting algorithm·the algorithm behind·design an algorithm·an efficient algorithm·the algorithm ranks

Synonyms

procedure·method·routine·formula·process

See also

Word family

algorithmic (adjective)·algorithmically (adverb)

In TOEFL & IELTS

A high-frequency academic and technology noun, common in Reading and Listening. It is a count noun — 'an algorithm', 'algorithms' — and collocates with follow, design, run, and optimize. The classic exam trap is logarithm: the two share letters and a rhythm but nothing else, so don't let the eye swap them. The adjective is algorithmic ('algorithmic trading'); stress falls on the first syllable, AL-go-rithm.