diagrammable

The story

1. Proto-Indo-European*dwóh₁
2. Proto-Indo-European*trísinflu.
3. Proto-Indo-European*dwís
4. Ancient Greekδιά (diá)
5. Ancient Greekδῐᾰ- (dĭă-)
6. Proto-Indo-European*gerbʰ-
7. Proto-Hellenic*grə́pʰō
8. Ancient Greekγρᾰ́φω (grắphō)
9. Ancient Greekγρᾰ́μμᾰ (grắmmă)
10. Ancient Greekδιάγραμμα (diágramma)
11. Italiandiagramma
12. Frenchdiagramme
13. Englishdiagram
14. English todaydiagrammable

From diagram + -able.