hy·pan·thi·um (hī-pān'thē-əm) n.
pl.hy·pan·thi·a (-thē-ə) The ringlike, cup-shaped, or tubular structure of a flower on which the sepals, petals, and stamens are borne, as in the flowers of the rose or cherry.
[New Latin : hyp(o)- + Greek anthos, flower.] hy·pan'thi·al adj.