| OPTER | • opter n. One who opts, or makes a choice. • OPTER n. someone who opts. |
| COPTER | • copter n. (Informal) A helicopter. • copter v. (Informal, transitive) To helicopter: to transport by helicopter. • copter v. (Informal, intransitive) To helicopter: to travel by helicopter. |
| ADOPTER | • adopter n. One who adopts. • ADOPTER n. one who adopts. |
| DIOPTER | • diopter n. A unit of measure of the power of a lens or mirror, equal to the reciprocal of its focal length in meters… • diopter n. The dioptre adjustment mechanism of a pair of binoculars or of a camera viewfinder. • diopter n. (Photography, dated) A lens element attached to the front of a photographic lens to shorten the lens’s… |
| HOROPTER | • horopter n. For any system of binocular vision, a three-dimensional curve containing all points from which the light… • HOROPTER n. a set of points which have the same visual angle. |
| CHIROPTER | • chiropter n. A member of the order Chiroptera, a bat. • CHIROPTER n. a type of bat. |
| COLEOPTER | • coleopter n. (Zoology) One of the Coleoptera. • COLEOPTER n. an aircraft that has an annular wing with the fuselage and engine on the centre line. |
| ORTHOPTER | • orthopter n. Any insect of the order Orthoptera. • orthopter n. Synonym of ornithopter. • ORTHOPTER n. a type of aircraft propelled with flapping wings. |
| GYROCOPTER | • gyrocopter n. (Aviation) An autogyro, similar to a helicopter. • GYROCOPTER n. an airplane balanced and supported by the aerodynamic forces acting on rapidly rotating horizontal or slightly inclined airfoils, also GYROPLANE. |
| HELICOPTER | • helicopter n. (Aviation) An aircraft that is borne along by one or more sets of long rotating blades which allow it… • helicopter n. A powered troweling machine with spinning blades used to spread concrete. • helicopter n. (Botany) The winged fruit of certain trees, such as ash, elm, and maple. |
| QUADCOPTER | • quadcopter n. A rotorcraft propelled by four rotors. • QUADCOPTER n. a pilotless four-rotor helicopter. |
| ORNITHOPTER | • ornithopter n. An aircraft that generates lift through the flapping of its wings. • ORNITHOPTER n. a birdlike archaic flying machine. |