Polyaenus of Lampsacus (/ˌpɒliːˈiːnəs/ POL-ee-EE-nəs; ‹See Tfd›Greek: Πoλύαινoς Λαμψακηνός, Polyainos Lampsakēnos; c. 340 – c. 285 BCE), also spelled Polyenus, was an ancient Greek mathematician and a friend of Epicurus.