per·i·car·di·um (pěr'ĭ-kär'dē-əm) n.
pl.per·i·car·di·a (-dē-ə) The membranous sac filled with serous fluid that encloses the heart and the roots of the aorta and other large blood vessels.
[New Latin, from Greek perikardion, from perikardios, around the heart : peri-, peri- + kardiā, heart; see kerd- in Indo-European roots.] per'i·car'di·al (-dē-əl), per'i·car'di·ac' (-dē-āk') adj.
Main Entry: peri·car·di·al Pronunciation: "per-&-'kärd-E-&l Function: adjective : of, relating to, or affecting thepericardium; also: situated around the heart