• The partially shaded outer region of the shadow cast by an opaque object.
  • The shadow cast by the Earth or moon over an area experiencing a partial eclipse.

Get a new word in your inbox every day.

By subscribing you are agreeing to our Privacy Policy and Terms of Use.

Example Sentences

“The moon cast a hazy penumbra over a section of Earth during the partial eclipse.”

“The sun was going down, but I could still see enough to walk by following the penumbras of the shadows.”

“I kept a close eye on the penumbra of the shadow so I would know the second the door started to move.”

Word Origin

Latin, mid-17th century

Why this word?

Eclipse watchers should know this word and its counterpart, “umbra.” During a partial eclipse, two shadows are cast. The umbra is the darker center that gets smaller as it moves away from the sun, and the penumbra is the smaller, lighter shadow that gets larger as it moves away from the sun. “Penumbra” comes from the Latin roots of “paene-” (meaning “almost”) and “umbra” (meaning “shadow”). Even when there’s not an eclipse, take a look around for the “almost shadow” around the edges of sharper shadows — as the angle of light changes, so will the penumbra.

  • More brands you’ll love

    Elevate Your Everyday

    More brands you’ll love

    Elevate Your Everyday

    Subscribe to Better Report to receive tips and tricks that will save you money, maximize your time, and improve your life.

    Subscribe to Better Report
    By clicking “Subscribe” you’re agreeing to Better Report Terms of Use and Privacy Policy

Learn a new word Abbozzo