A form of digital media on a plastic disc read by a laser in a CD drive. It comes in several varieties including CD-ROM, CD-R, and CD-RW.

(navigation) A graduated circle, usually marked in degrees, indicating directions and printed or inscribed on an appropriate medium.

(historical) A device used to impress a company's name and/or symbol onto a dollop of soft red wax attached to a legal instrument, where two directors or one director and the secretary could sign as witnesses, thus executing the instrument.

One who complains, or is known for their complaints.

One companion is better than two.

Having the characteristics of a worthy companion; friendly and sociable.

(military, nautical) An instrument containing a freely suspended magnetic element which displays the direction of the horizontal component of the Earth’s magnetic field at the point of observation.

(geometry, geomagnetism) The combination of variation and deviation which is the horizontal angle between the direction indicated by a magnetic compass and true north.

(nautical) Either of two ladders leading from the raised quarterdeck of a sailing ship to the upper deck.

(mathematics) Any topological subset of Euclidean space that is a compact set