Grain is orbicular to ovate, concavo-convex, red-brown, and transversely rugose.    From Wordnik.com.  [A Handbook of Some South Indian Grasses] Reference

Grain is oblong, obtusely trigonous, or concavo-convex, red-brown and rugulose on the ventral side.    From Wordnik.com.  [A Handbook of Some South Indian Grasses] Reference

The coins of these two Greek states in particular were for a long period concavo-convex disks, the convex side being in all instances the obverse.    From Wordnik.com.  [The New England Magazine Volume 1, No. 6, June, 1886, Bay State Monthly Volume 4, No. 6, June, 1886] Reference

—In this variety the opposing surfaces are reciprocally concavo-convex.    From Wordnik.com.  [III. Syndesmology. 3. Classification of Joints] Reference

"Why do you weep?" he asked, peering at the Boy through his concavo-convex Nose Glasses.    From Wordnik.com.  [Fables in Slang] Reference

On its anterior surface is a deeply concavo-convex facet, which articulates with the head of the malleus.    From Wordnik.com.  [X. The Organs of the Senses and the Common Integument. 1d. 3. The Auditory Ossicles] Reference

Angular bits of iron, concavo-convex, sticking in the sides of muddy depressions, showed where shells had exploded in their furrows.    From Wordnik.com.  [The Collected Works of Ambrose Bierce, Volume 1] Reference

Its upper surface is concavo-convex from before backward, to accommodate itself to the form of the mandibular fossa and the articular tubercle.    From Wordnik.com.  [III. Syndesmology. 5d. Articulation of the Mandible] Reference

By these it is seen that a double-convex lens tends to condense the rays of light to a focus, a double-concave to scatter them, and a concavo-convex combines both powers.    From Wordnik.com.  [American Hand Book of the Daguerreotype] Reference

The base presents a concavo-convex surface, for articulation with the greater multangular; it has no facets on its sides, but on its radial side is a tubercle for the insertion of the Abductor pollicis longus.    From Wordnik.com.  [II. Osteology. 6b. 2. The Metacarpus] Reference

The Fifth Metacarpal Bone (os metacarpale V; metacarpal bone of the little finger) (Fig. 233) presents on its base one facet on its superior surface, which is concavo-convex and articulates with the hamate, and one on its radial side, which articulates with the fourth metacarpal.    From Wordnik.com.  [II. Osteology. 6b. 2. The Metacarpus] Reference

Below the frontonasal suture is the bridge of the nose, convex from side to side, concavo-convex from above downward, and formed by the two nasal bones supported in the middle line by the perpendicular plate of the ethmoid, and laterally by the frontal processes of the maxillæ which are prolonged upward between the nasal and lacrimal bones and form the lower and medial part of the circumference of each orbit.    From Wordnik.com.  [II. Osteology. 5c. The Exterior of the Skull] Reference

A shifting and changeable variety of dimensions, shades, and colours; while the two mediums, assisted by the concavo-convex shape of the vessel, magnify and distort them vastly; not to mention that the introduction of another element and its inhabitants into our parlours engages the fancy in a very agreeable manner.    From Wordnik.com.  [The Natural History of Selborne, Vol. 2] Reference

Lenses for the photographic camera are now always ground of a concavo-convex form, or meniscus, which corresponds more nearly to the accompanying diagram. ".    From Wordnik.com.  [American Hand Book of the Daguerreotype] Reference

Fig. 7 a concavo-convex or meniscus.    From Wordnik.com.  [American Hand Book of the Daguerreotype] Reference