English Reference
noun

expectancy

n.
US /ɪkˈspɛktənsi/ UK /ɛkspˈɛktənsi/ ex·pectan·cy UK spelling expectancies

  1. 01 B2 Upper Intermediate

    the feeling that something is about to happen, especially something good.

    the state of thinking or hoping that something, especially something pleasant, will happen soon.

    Simple

    There was a sense of expectancy in the crowd as they waited for the singer to appear.

    In context

    An air of quiet expectancy filled the courtroom as the jury returned to deliver their final verdict after three days of deliberation.

  2. 02 B2 Upper Intermediate Science

    the number of years that a person or thing is likely to live or last.

    the average period that a person may expect to live, or that an object is expected to remain functional.

    Simple

    Better healthcare has led to a higher life expectancy in many countries.

    In context

    Public health officials noted that life expectancy had plateaued in the region due to rising rates of sedentary lifestyle diseases.

    Usage

    Often used in the compound 'life expectancy'.

  3. 03 C1 Advanced Technical Math

    the average value you expect to get from a set of data or a chance.

    the predicted value of a variable, calculated as the sum of all possible values each multiplied by the probability of its occurrence.

    Simple

    The mathematical expectancy of the game shows that the house always wins.

    In context

    In statistical theory, the expectancy of a random variable provides a measure of the center of its distribution.

    Usage

    Used as a technical synonym for 'expected value' in probability and statistics.

    expected valueprobability
  4. 04 C2 Proficiency FormalTechnical Law

    a right to own or use something in the future, even if you do not have it yet.

    a potential future interest in property or an estate that has not yet vested.

    Simple

    The heir had a legal expectancy to the family estate once his uncle passed away.

    In context

    The court ruled that a mere expectancy of inheritance does not constitute a present property right in divorce settlements.

Usage life expectancy

The press-ups check strength and muscular capacity, both of which can give a sense of overall risk of disease, as well as life expectancy.

The Guardian· 2 Sept 2026

Adding to this is an average Amish life expectancy of 81.2 years, which is a few years longer than the average American life expectancy.

Phys.org· 12 Aug 2026

From expectant + -cy or expect + -ancy.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated