in the fountain pen world we call the "spread out" effect "feathering" I always thought it was a cool name :)

In France we call the fountain pen Stylo Plume. Which literally stands for Feather Pen. And the part from which the ink flow is called the plume (feather).

In this context, “plume” would probably be translated to “quill” rather than “feather” (or “nib”, for the metal bit that touches the paper). It’s ambiguous in French, because if is the same word for the bird thing and the writing instrument.

Same in Spanish with “pluma” for the writing tool and the bird-thing.