Pertaining to, or in accordance with, the doctrine of panpsychism.
1984, Timothy Sprigge, Santayana and Panpsychism, in Overheard in Seville: Bulletin of the Santayana Society, No. 2: Fall 1984, page 1,
Santayana was certainly not a panpsychist. However, I believe that there are panpsychist tendencies in his work.