Definitions
 1) skateboarding An indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.
 2) surfing An indentation running along the base of a surfboard, intended to increase lift.
 3) The vault of the sky.
 4) One of the celestial spheres of the Ptolemaic or geocentric model of the world.
 5) A concave surface or curve.
 6) manufacturing An element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.
 7) A concave surface, structure, or line.
 8) (Mech.) A curved sheath or breasting for a revolving cylinder or roll.
 9) A hollow; an arched vault; a cavity; a recess.
 10) Any inwardly curved portion of a machine: as, the concave of a thresher (the curved breast in which the cylinder works).
 11) A concave mirror.
 12) A playing card so trimmed that it can be separated from others according to the purpose for which the pack was prepared.
 13) The vault or arch of heaven: as, “the blue concave.”
 14) A hollow; an arch or vault; a concavity.
 15) curved like the inner surface of a sphere or bowl
 16) Curved like the inner surface of a sphere.
 17) Hollow and curved or rounded; vaulted;  said of the interior of a curved surface or line, as of the curve of the of the inner surface of an eggshell, in opposition to convex.
 18) rare Hollow; void of contents.
 19) curving inward
 20) To render concave, or increase the degree of concavity.
 21) Tomakehollow.
 22) To make hollow.
 23) Curved or rounded in the manner of the circumference of a circle or the surface of a sphere when viewed from the center; presenting a hollow or incurvation; incurved; hence, bounded by such a line or surface: as, a concave mirror.
 24) Hollow; empty.
 25) Hollow;empty.
 26) To make concave.
 27) To make hollow or concave.

Definitions
 1) Any convex body or surface.
 2) A convex body or surface.
 3) [⟨ L. convexum, prop. neut. of convexus, adj.: see above.] A convex body or surface.
 4) curved or bowed outward like the outside of a bowl or sphere or circle
 5) analysis, not comparable (of a realvalued function on the reals) such that the value at any point, is no larger than the interpolated value thereat, based on the values at any two points between which the first point is contained
 6) mathematics, not comparable (Of a set of points) such that for any two points in the set, every point between those two points is also in the set
 7) Having a surface or boundary that curves or bulges outward, as the exterior of a sphere.
 8) Rising or swelling into a spherical or rounded form; regularly protuberant or bulging;  said of a spherical surface or curved line when viewed from without, in opposition to concave.
 9) convex on both sides; convexoconvex.
 10) curving or bulging outward
 11) In geometry, having no reëntrant angle.
 12) Curved, as a line or surface, in the manner of a circle or sphere when viewed from some point without it; curved away from the point of view; hence, bounded by such a line or surface: as, a convex mirror.
 13) Specifically In zöol. and anatomy, elevated and regularly rounded; forming a segment of a sphere, or nearly so: distinguished from gibbous, which is applied to a less regular elevation.

Examples
 1) Nothing greeted her touch but a smooth, gently concave surface.
 2) ‘Galileo's telescope had a convex object lens but a concave eyepiece.’
 3) ‘The articular surface itself is concave, not convex as in many chelonioids.’
 4) ‘Depressions are concave regions on protein surfaces that have no constriction at the mouth.’
 5) ‘Similar double curvatures were used for concave lenses, and even more complicated corrections for astigmatism.’
 6) ‘McElwee contrasts convex and concave forms with building recesses and relief carvings.’
 7) ‘You stand in a dark room looking at a round concave surface perhaps five feet in diameter.’
 8) ‘Choose only firm tubers and look for those with tiny sprouts showing on their upper, concave surfaces.’
 9) ‘This is a small group of specialized ellesmerocerids with a concave outline of siphuncle segments.’
 10) ‘If the outside edges appear to get sanded first, yet the middle part isn't affected, then you have a concave surface.’
 11) ‘Its profile may show anything from a rather gentle concave upward curve to a series of complex scarps and sedimentfilled basins.’
 12) ‘The shape of each is similar, with a slightly concave surface, a rolled rim, and a high foot ring.’
 13) ‘The first surface of the head support arm is concave and the second surface of the head support arm is convex.’
 14) ‘The human shoulder blade is a thin triangle of bone with a thick crest along one edge, and a shallow, concave joint surface in one corner.’
 15) ‘You maintain your lower back curve, which is concave, by sitting straight in your chair.’
 16) ‘Where the old car had concave surfaces on the doors, the new doors swell outwards, lending more bulk to the profile.’
 17) ‘As the enamel shrinks on melting and cools with a concave surface, more has to be poured in and the process repeated.’
 18) ‘It is possible to see the outline of a concave façade and shallow forecourt.’
 19) ‘Pictures of bound feet show the toes bent right under the sole, which is so curved it is concave.’
 20) ‘Above it, to signal the presence of occupied space, is a shallow concave circle dug out of the ground.’
 21) ‘The exterior walls were composed of concave and convex red bricks.’

Examples
 1) And owls, I hear, have eyes as big as the glasses of a convex lamp.
 2) The convex shape of the hill made approaches to it from below difficult to detect.
 3) Caspar, a blessing of a human being, with his expression as open as a convex mirror.
 4) The bowed t bar also called a convex t bar is usually found either in the center or the top of the stem.
 5) Such lenses are called convex or converging lenses.
 6) Those are tools useful in the field of convex processing, and more precisely to solve a problem called convex feasbility ...
 7) Emphasis is on route planning and recognizing dangerous terrain features such as convex rolls, gullies and windloaded slopes.
 8) Leipsic, Essling, and Brienne he used a kind of convex order very like
 9) Got a good one on the last quiz ... the correct answer to the question was "convex" (the shape) the student was apparently thinking "concave" (a related shape) « Reply #454 on: Yesterday at 02: 16: 41 PM »
 10) As illustrated in the chart below, data going back to 1970 shows that the US Dollar Index (an average of the greenback's value against six of its top counterparts) is higher when US Gross Domestic Product growth rates are either sharply above or below the average of other G7 nations; it is lower when the difference in growth rates declines, revealing a "convex" relationship or a
 11) ‘Galileo's telescope had a convex object lens but a concave eyepiece.’
 12) ‘Carve out squares of curving surfaces, concave and convex.’
 13) ‘While the pillows are still partially molten they are compacted together so that they display convex upper surfaces and downwardsfacing cusps at their contacts.’
 14) ‘For the ceiling, he ‘proposed a series of convex surfaces,’ lowered toward the front.’
 15) ‘Light enters the human eye via the transparent cornea, the eye's front window, which acts as a powerful convex lens.’
 16) ‘The steroid treatment consisted of three implants per ear inserted subcutaneously on the convex surface of the ear.’
 17) ‘The tongue normally offers a convex surface to the roof of the mouth: for an rsound, the tongue surface is often hollowed out and the tip raised.’
 18) ‘It weighs 440 g. One surface is smoothly convex and may have been used as a grinding stone.’
 19) ‘This particular beach is many miles long and shaped like a new moon, a convex curve extending into the Gulf of Mexico.’
 20) ‘Through the convex lens these frozen moments in time are of the other ‘side’.’
 21) ‘Powerful images captured through a convex lens are frozen in time.’
 22) ‘He likened this to asking an artisan to explain how the convex surface of a peg can possibly fill that of a concave hole.’
 23) ‘Surprised, Jeana turned to look at her reflection in the mirror with the convex surface.’
 24) ‘From the level of tooth one to tooth five, the lateral surface is slightly convex.’
 25) ‘Ridges on the convex surface are not as well developed as those on the flat surface.’
 26) ‘Sometimes, highlighted down the middle where the trees grew tall, the surface could look convex.’
 27) ‘Go for a nice belly in the blade  a nice convex curve seriously improves cutting.’
 28) ‘The water column was lowered over the dry grains until the convex surface just touched them.’
 29) ‘The exterior walls were composed of concave and convex red bricks.’
 30) ‘With water the surface is concave, with mercury it is convex.’
 31) ‘A convex polygon with a triangle attached to one of its edges in this way is called a barbed polygon.’
 32) ‘We used convex polygons to estimate distances between colony centers and the size of each colony to define the area of burrows in use by a family group in a current season.’
 33) ‘The 95% minimum convex polygon was estimated for each bird using all sightings.’
 34) ‘Calculating the convex polygon for the immature male resulted in an inaccurate representation of his movement patterns.’
 35) ‘However, despite such examples, it is commonly believed that if you restrict yourself to looking at convex polygons, this question has a positive answer.’
