said of corolla or calyx (or flower) when divisible into equal halves in one plane only; zygomorphic.
capable of division into symmetrical halves by only one longitudinal plane passing through the axis
having identical parts on each side of an axis
bi-LAT-er-a-lee sim-MET-rik-al An animal body form in which only one plane divides the animal into mirror image halves. 512
can be divided into equal halves with a head and a rear
Referring to an organ which can be divided in only one place to yield mirror-image halves.