The reader will find in these pages (fulfilling the need for a sufficiently broad, serious and adjusted lexicon) a basic terminological dictionary of Galen which makes easier the reading of his texts in their original language (Greek). We must not forget that the Galenic corpus, even with all that has been lost over time, is still immense (22 vols. in Kühn’s Greco-Latin version). Despite this, it can be noticed just by reading his works that his terminology is deep, extremely large and highly dense. This work is an attempt to achieve this mission.