Medieval translators chose the term quwwa to render the Greek dynamis since the two terms mean “strength, potency, power, force”. Besides dynamis and quwwa were used as technical terms in Greek and Arabic philosophy. Despite of the fact, they did not have only one meaning, but many according to authors and to the subject matter. The article focuses on the meanings of the term quwwa intended by Ibn Bāğğa (Avempace, ca. 1085-1139) in three of his commentaries on Aristotle’s books On
Coming-to-Be and Passing-Away, the Physics, and his treatises History of Animals,
On the Parts of Animals and Generation of Animals put together into a Book of Animals in the Arabic tradition.