probability

/ˌprɑːbəˈbɪləti/

Say it: prob-uh-BIL-ih-tee

1. noun The mathematical measure of how likely an event is to occur, expressed as a number between 0 (impossibility) and 1 (certainty).
The probability of flipping a coin and getting heads is 0.5, or 50%.
2. noun The quality of being likely to happen or be true; a strong likelihood.
There is a high probability that the new policy will face significant opposition.
3. noun An event or outcome that is likely to happen.
A tax increase next year is a strong probability.

📖 Seen in the wild

There is a high probability of rain later this afternoon, so bring an umbrella.
collected by @vocablast

✏️ probability in a sentence

In all probability, the package will arrive by Friday.
The weather forecast gives a 90% probability of rain.
We calculated the statistical probability of a system failure during peak hours.
What's the probability of you being free for dinner this week?
He weighed the probabilities and decided the risk was too great.
Probability theory is a fundamental branch of mathematics with applications in science, finance, and gambling.
The defense attorney argued that the probability of his client being at the scene was extremely low.

🔁 Synonyms & antonyms

likelihood chance odds prospect likeliness possibility feasibility

likelihood · a very close synonym, but often used more generally and less mathematically.

chance · suggests randomness or luck and is often used in less formal contexts.

odds · specifically refers to a ratio of favorable to unfavorable outcomes, common in statistics and gambling.

prospect · implies a future possibility, often with a positive or negative outlook.

Opposites: improbability, impossibility, certainty, unlikelihood

🌱 Where it comes from

The word 'probability' comes from the Latin 'probabilis', meaning 'provable' or 'worthy of belief'. Originally, it referred to the authority of a witness in a legal case. Its modern mathematical sense, referring to the likelihood of an outcome, developed in the 17th century with the work of mathematicians like Pascal and Fermat, who were studying games of chance.

🧩 How it's used

Common patterns:

high/low probabilitystatistical probabilityprobability of successin all probabilityprobability theorybalance of probabilities

While 'probability' and 'possibility' are related, they are not interchangeable. A possibility is something that could happen (its probability is greater than zero), while probability quantifies how likely it is to happen. Use 'probability' when you want to specify the degree of likeliness, even if you are not using a precise number. For example, saying there's a 'high probability' of rain is more specific than saying there's a 'possibility' of rain.

Word family: probable, probably, improbable, improbability

💬 Quick answers

What does probability mean?

Probability is the measure of how likely something is to happen. It's often represented as a number between 0 (impossible) and 1 (certain).

What is the difference between probability and possibility?

Possibility means something can happen, whereas probability measures how likely it is to happen. It's possible to win the lottery, but the probability is extremely low.

What does the phrase 'in all probability' mean?

It's a common idiom that means 'very likely' or 'almost certainly'. For example, 'In all probability, the train will be on time.'

Is probability a formal word?

Probability is a neutral word. It is used in highly technical and formal contexts like mathematics and science, but it is also common in everyday conversation.

1 word nerd collected it V

Want "probability" to actually stick?

Save it to your own vault, let AI explain it, practice till it's yours.

Start for free →