From The Collaborative International Dictionary of English v.0.48 :
Carina \Ca*ri"na\, n. [L., keel.]
1. (Bot.) A keel.
(a) That part of a papilionaceous flower, consisting of
two petals, commonly united, which incloses the organs
of fructification.
(b) A longitudinal ridge or projection like the keel of a
boat.
[1913 Webster]
2. (Zool.) The keel of the breastbone of birds.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
Carina
n 1: a keel-shaped constellation in the southern hemisphere;
contains the start Canopus
2: any of various keel-shaped structures or ridges such as that
on the breastbone of a bird or that formed by the fused
petals of a pea blossom