We found 2 dictionaries that define the word writing inks:

General (2 matching dictionaries)

1. writing inks: Merriam-Webster
2. writing inks: Vocabulary.com

(Note: See writing_ink as well.)

Definitions from WordNet (writing ink) ▸ noun:  any permanent or washable ink used with pens ▸ Also see writing_ink ▸ Words similar to writing inks ▸ Usage examples for writing inks ▸ Idioms related to writing inks ▸ Wikipedia articles (New!) ▸ Words that often appear near writing inks ▸ Rhymes of writing inks ▸ Invented words related to writing inks