Category: B

With two horns.  

Domed on two sides; also lenticular. Having convex faces on both sides. Having a surface on each side that curves outward. Biconvex lenses are used to correct far-sightedness. Convex on two sides, especially as a type of lens.  

Having a hollowed surface on both sides. Biconcave lenses are used to correct near-sightedness. Having concave faces on both sides. Referring to a lens which is concave on both sides. Concave on each side, especially as a type of lens.  

With two colours.    

With two caruncles.  

With an ovary made up of two carpels.  

With two keels.  

With two heads.  

With two spurs.  

With two bracteoles.