plan·u·la (plān'yə-lə) n.
pl.plan·u·lae (-lē') The flat, free-swimming, ciliated larva of a coelenterate.
[New Latin plānula, from Latin, feminine diminutive of plānus, flat (from its shape); see pelə-2 in Indo-European roots.] plan'u·lar, plan'u·late' (-lāt') adj.