English Reference
adjective · noun

constant

adj. · n.
US /ˈkɑnstənt/ UK /kˈɒnstənt/ con·stant UK spelling constants

  1. 01 B2 Upper Intermediate

    adj.happening again and again or staying the same for a long time.

    adj.occurring continuously or recurring frequently over a period of time.

    Simple

    The constant noise from the construction site made it hard to sleep.

    In context

    The project was delayed by constant interruptions and a lack of clear leadership from the department head.

  2. 02 B2 Upper Intermediate Academic Science

    adj.staying at the same level, speed, or value.

    adj.remaining invariant or unchanging in nature, value, or intensity.

    Simple

    The pilot maintained a constant speed throughout the flight.

    In context

    Maintaining a constant temperature is critical for the success of this chemical reaction.

  3. 03 C1 Advanced AcademicTechnical Math

    n.a number or value that does not change during a calculation or experiment.

    n.a quantity or parameter that does not change its value throughout a given mathematical operation or scientific discussion.

    Simple

    In this math problem, 'g' represents the constant for gravity.

    In context

    The researcher identified the atmospheric pressure as a constant to simplify the initial stages of the simulation.

    fixed valueinvariant
  4. 04 C1 Advanced Technical Computing

    n.a name in computer code that represents a value that cannot be changed while the program is running.

    n.an identifier bound to an invariant value, used in source code to improve readability and prevent accidental modification.

    Simple

    The programmer defined the maximum number of users as a constant.

    In context

    By using a constant for the API endpoint, the developers ensured that the URL remained consistent across the entire application.

    Usage

    In many programming languages, constants are written in ALL_CAPS by convention.

    literalfinal variable

Usage constant noise · constant threat

Neighbours have complained about fires and for months there was a constant hum from electrical generators.

BBC News· 15 Aug 2026

They are an amazing team, and have remained in constant communication, helping us greatly throughout this awful time.

BBC News· 15 Aug 2026
This entry
Level B2 · Upper Intermediate
Frequency Common
Updated