adj

• (functional analysis, not comparable, of a real-valued function on the reals) having an epigraph that is a convex set.
• (geometry, not comparable, of a polygon) having no internal angles greater than 180 degrees.
• (mathematics, not comparable, of a set in Euclidean space) arranged such that for any two points in the set, a straight line between the two points is contained within the set.

noun

• (gambling) A playing card made convex for use in cheating.
• (gambling) A small convex mirror used to cheat by observing other players' cards.
  "Of all the devices for defrauding at poker, the “shiner,” or “convex” […] Modern convexes are also considerably larger than those of former days."

verb

• (intransitive) To form a convex curve or surface; to become convex.
  "In like manner the north pier will convex seaward, extending across the bay to the extent of 1000 feet from low water, terminating in about eight fathoms, leaving a clear entrance of 500 feet between the pier heads, the depth of the entrance being from seven to eight fathoms."
• (transitive) To cause to form a convex curve or surface; to make convex.
  "The back edge of the saw being under the lip of the cleat, use the anvil for a fulcrum and press down on the edge of the saw opposite, which will convex the plate, as the springing up concaved it, and the action of the fast and loose will be the reverse; that is, the fast will go down and the loose come up."
• (ambitransitive) To circulate or cause to circulate in a curved path; to cause or exhibit convection.
  "The crystal/melt interface thus convexes into the melt; however, the convexity of the interface ( Figure 53 ) is not as strong as it is when the crucible does not rotate (Figure 52)."