adjective

stochastic

stuh-KAS-tik

Stochastic (adjective) means involving or governed by chance, so that individual outcomes cannot be predicted exactly even though the pattern of outcomes over many trials can be described by probability. Example: “Share prices are usually modelled as a stochastic process rather than a fixed curve.”

adjective

Involving or governed by chance, so that individual outcomes cannot be predicted exactly even though the pattern of outcomes over many trials can be described by probability.

"Share prices are usually modelled as a stochastic process rather than a fixed curve."

"Radioactive decay is stochastic: you cannot say which atom will decay next, only how many will."

technical Of a computational method: using randomly chosen samples or steps rather than working through every possibility, in order to reach a good answer faster.

"Stochastic gradient descent updates the model from one small batch at a time instead of the whole dataset."

How to Use Stochastic

Learner’s notes

In plain EnglishDriven by chance, so you can predict the overall pattern but not any single result.

When to use it

Technical. Common in statistics, finance, physics and machine learning; rare in ordinary conversation.

Memory tip

If you can swap in "random-but-with-known-odds", stochastic is the right word.

Trace the full origin ↓

Easily confused with

deterministic chaotic → probabilistic

Common pairings

stochastic process stochastic model stochastic gradient descent stochastic variable

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Fill the Gap

Can you complete this real example?

Share prices are usually modelled as a _____ process rather than a fixed curve.

Etymology

From Greek stokhastikos "able to guess, skilled at aiming", from stokhos "a mark or target aimed at".

Origin: Greek

Synonyms

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random probabilistic chance aleatory non-deterministic randomised Monte Carlo

Antonyms

deterministic predictable

Related Words

chance happen risk opportunity luck accident possibility familiar

Rhymes for stochastic

plastic elastic drastic monastic fantastic sarcastic scholastic enthusiastic

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Frequently Asked Questions

What is the difference between stochastic and random?

In everyday speech they overlap, but "random" describes a single unpredictable event while "stochastic" describes a system or process whose behaviour over time follows a probability distribution. A coin flip is random; the sequence of thousands of flips is a stochastic process.

What is the difference between stochastic and deterministic?

A deterministic system always produces the same output from the same starting conditions. A stochastic one includes an element of chance, so the same starting conditions can produce different outcomes each time it runs.

How do you pronounce stochastic?

Stuh-KAS-tik, with the stress on the second syllable. The "ch" is a hard k sound, as in "chaos".

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