Merriam-Webster Collegiate Dictionary - epithalamium

 or epithalamion  noun  (plural -miums or epithalamia)  Etymology: Latin & Greek; Latin ~, from Greek epithalamion, from epi- + thalamos room, bridal chamber; perhaps akin to Greek tholos rotunda  Date: 1588 a song or poem in honor of a bride and bridegroom  • epithalamic adjective EPITHELIAL  adjective  Date: 1845 of or relating to epithelium