| ADOPTERS | • adopters n. Plural of adopter. • ADOPTER n. one who adopts. |
| CHIROPTERS | • chiropters n. Plural of chiropter. • CHIROPTER n. a type of bat. |
| COLEOPTERS | • coleopters n. Plural of coleopter. • COLEOPTER n. an aircraft that has an annular wing with the fuselage and engine on the centre line. |
| COPTERS | • copters n. Plural of copter. • COPTER n. (short for) a helicopter. |
| DIOPTERS | • diopters n. Plural of diopter. • DIOPTER n. a measure of refractive power, also DIOPTRE. |
| GYROCOPTERS | • gyrocopters n. Plural of gyrocopter. • GYROCOPTER n. an airplane balanced and supported by the aerodynamic forces acting on rapidly rotating horizontal or slightly inclined airfoils, also GYROPLANE. |
| HELICOPTERS | • helicopters n. Plural of helicopter. • helicopters v. Third-person singular simple present indicative form of helicopter. • HELICOPTER v. to travel by helicopter. |
| HOROPTERS | • horopters n. Plural of horopter. • HOROPTER n. a set of points which have the same visual angle. |
| OPTERS | • opters n. Plural of opter. • OPTER n. someone who opts. |
| ORNITHOPTERS | • ornithopters n. Plural of ornithopter. • ORNITHOPTER n. a birdlike archaic flying machine. |
| ORTHOPTERS | • orthopters n. Plural of orthopter. • ORTHOPTER n. a type of aircraft propelled with flapping wings. |
| QUADCOPTERS | • quadcopters n. Plural of quadcopter. • QUADCOPTER n. a pilotless four-rotor helicopter. |