Penumbra 

An amazing gothic metal band from France. Similar to bands like trail of tears, sirenia, tristania and therion.

Listen to the album "Seclusion", highlight of Penumbra

Penumbra by artyq729 November 18, 2006

penumbra 

The shadow cast by a partial eclipse.
Surrounds the Umbra.

The total eclipse was only over New york, but all of New England was in the Penumbra.

penumbra by pythonspam November 7, 2003

Penumbra 

a friendgroup consisting of a server of dumb people who say funny stuff sometimes.

"hey whats that group of people over there saying stupid shit and being annoying?"

"oh, thats Penumbra."

Penumbra by cakecharm July 9, 2024

Penumbra

(Adjective) Deltarune theorising: refers to a theory or plot point's use of metaphysical elements, particularly in replacement of existing narrative material

"Gaster corrupted Dess into the Knight in the bunker"

"Dude, that's penumbra slop"

Penumbra by polygloid June 13, 2026

Penumbra Black Plague 

Possibly the best horror game on the planet working in five hours (unfortunately) of intelligent gameplay and brilliant story accompanied by a feeling of vulnerability as the only thing you can use is the ability to run from the skeletal monsters that _can and will kill you_. Lacking in some texture detail but excelling in every other aspect including but not limited to atmosphere, brilliant soundtrack, admirable voice acting, compelling story, very interactive physics, psychological destruction, and challenging puzzles, this game is simply amazing.

Penumbra Black Plague is the shit man.

Penumbra Black Plague by lee wolfgang April 13, 2009

penumbra phantasmic

Describing dialogue or writing that throws every recurring Deltarune buzzword and cryptic phrase into a blender until it feels profound, regardless of whether it actually means anything.

Named after Penumbra Phantasm, an unreleased Toby Fox song that fans spent years theorizing would appear in Deltarune, until Toby Fox confirmed it would never be used in the game, causing it to become a fandom meme.

Ramb: "Freedom's just a penumbra phantasm for big shots about the world revolving."
Player: "This dialogue is so penumbra phantasmic."

A: "Copies are monochrome... very, very interesting. Shadows cut deeper. Darker, yet darker."
B: "Dude, stop writing so penumbra phantasmic."

penumbra phantasmic by MegaPiggy June 28, 2026

Penumbation 

Penumbation (noun)

The act of penumbating.

Jason demonstrated penumbation to his peers while aspirating acute thrombus.

Penumbation by Interventionalist August 21, 2018