The phrase fountain pen is a noun. Fountain Pen means (1) a pen that is supplied with ink from a reservoir in its barrel.
The following articles and web pages elaborate on the phrase fountain pen.
A fountain pen is technically any pen that holds and releases its ink, but usually refers to a pen with an exposed or hooded split metal point. Learn more with this fountain pen collecting guide.
https://www.fountainpens.us/collecting.htm
Fountain pens are a classy writing utensil and make sophisticated gifts. They are available in nine different nib sizes in three nib cuts: straight, oblique, and italic.
https://www.fountainpens.us/
Browse this newspaper publisher directory for info about newspaper publishers in the United States of America. The photo on this page shows a newspaper, with reading glasses and fountain pen.
https://newspaper-publishers.regionaldirectory.us/
The following article provides recent fountain pen-related news.
An Air China flight had to be diverted after a passenger held a crew member hostage using a fountain pen as a weapon.
Sky News. Sunday, 15 Apr 2018 16:23:00 +0100.
The following digital image illustrates the phrase fountain pen.