Feather Mean

Feather in Adobe: Not About Birds

Feather in Adobe software refers to the process of softening the edges of a selection. It's like gradually fading the selection into the surrounding area, creating a smooth transition instead of a harsh cut-off.

The term likely comes from the visual similarity to the soft, gradual transition between a bird feather's barbs and the surrounding air. It's a descriptive metaphor for the effect achieved in digital image editing.

The word 'feather' can be used in way more situations than bird feathers.

https://www.merriam-webster.com/dictionary/feather

This should cover the subject: https://www.bwillcreative.com/what-is-feathering-in-photoshop-and-how-to-use-it/