The side of a cassette tape or record that holds the primary track. / (by extension) The track on the A-side of a tape or record. / The first track on a compact disc single.

plural of side.

Third-person singular simple present indicative form of side

present participle of side

(rail transport) A second, relatively short length of track just to the side of a railroad track, joined to the main track by switches at one or both ends, used either for loading or unloading freight, storing trains or other rail vehicles; or to allow two trains on a same track to meet (opposite directions) or pass (same direction) (the latter sense is probably an American definition).

(Canada, US) A building material which covers and protects the sides of a house or other building.

simple past tense and past participle of side

Separate from the main course of a meal. / Supplementary or in addition to one's usual job or income. / Additional, surreptitious; often with a connotation of dishonesty, illegality or adultery.

(geography, historical) An ancient city on a small peninsula on the Mediterranean coast of Anatolia, settled by Greeks from Cyme.

present participle of side with