plenilunium
/ˌpliːnɪˈl(j)uːnɪəm/ /ˌplɛnɪˈl(j)uːnɪəm/noun
A full moon; the time of a full moon; = plenilune.
Origin
Early 17th century; earliest use found in Thomas Tomkis (b. c1580), playwright. From classical Latin plēnilūnium time of full moon from plēni- + lūna + -ium.