The Open Dictionary

cumulus

noun

UK/ˈkjuː.mjə.ləs/
US/ˈkjuː.mjə.ləs/

Definitions of cumulus noun

  1. Uncountableenvironment

    a type of cloud that is tall and white, characterized by a broad, flat base and a rounded, puffy top.

    • On a sunny day, the sky was filled with fluffy cumulus clouds.

    • The cumulus clouds began to build higher as the afternoon progressed.

    • Cumulus clouds often form over mountain peaks in hot weather.