I. (ˈ)hī|pyu̇rəl adjective
Etymology: hypo- + ur- (tail) + -al
: of, relating to, or constituting the bony structure chiefly formed of the expanded and more or less fused hemal spines of the last few vertebrae that supports the caudal fin rays in most teleost fishes
II. noun
( -s )
: a hypural bone