English Reference
noun

wavelength

n.
US /ˈweɪvˌɫɛŋθ/ UK /wˈeɪvlɛŋθ/ wave·length UK spelling wavelengths

  1. 01 B2 Upper Intermediate Technical Science

    the distance between two peaks of a wave, like light or sound.

    the distance between successive crests or troughs of a wave, particularly of electromagnetic radiation or sound.

    Simple

    Different colours of light have different wavelengths.

    In context

    The telescope is designed to detect infrared radiation at a specific wavelength that is normally invisible to the human eye.

    Usage

    Often used with the preposition 'at'.

  2. 02 B2 Upper Intermediate Informal

    a way of thinking or a set of ideas that you share with someone else.

    a state of agreement or mutual understanding regarding ideas, feelings, or philosophy.

    Simple

    We work well together because we are on the same wavelength.

    In context

    It was refreshing to meet a business partner who was on the same wavelength regarding the long-term sustainability of the project.

    Usage

    Almost always used in the phrase 'on the same wavelength'.

Usage wavelengths of light

Radio waves have wavelengths much longer than what human eyes can see.

Phys.org· 16 Aug 2026

The team also observed another strange pattern: The dot's light was extremely bright, except below certain wavelengths, where the light completely disappeared.

Phys.org· 16 Aug 2026

From wave + length.

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

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated