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Number & MeasureGreekEnglish

Stochastic

/stəˈkæstɪk/adjective

Governed by probability rather than fixed rule, so that outcomes vary randomly around a pattern.

The Greek roots

στοχαστικός
stokhastikós
able to guess, skilled at aiming
+
στόχος
stókhos
aim, target

Literally: good at aiming

The story of the word

The root is archery. A στόχος is the mark you shoot at, and στοχαστικός describes the man who is good at aiming, which in Greek slides easily into good at guessing. English borrowed it in the 1660s to mean conjectural, then largely dropped it. Probability theory pulled it back in the 1930s, and it now means something the Greeks would have recognised anyway: you aim, and you find out where you landed.

How it travelled
Ancient Greek → English
First recorded
1660s

The same roots elsewhere

Other languages reached for exactly the same Greek pieces.

In a sentence

Queue lengths follow a stochastic process, so the average tells you less than you think.

They modelled demand stochastically rather than picking a single forecast.

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