A·qui·nas  (ə-kwī'nəs)  Italian Dominican friar, theologian, and philosopher. The most influential thinker of the medieval period, his philosophy combined Aristotelianism and elements of Neo-Platonism within a context of Christian thought. His works include the Summa contra gentiles (1259-1264) and the Summa theologiae or theologica (1266-1273). |