1. The upper side. Upside down, the upper part undermost; in complete disorder.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• alside,
• updside,
• asside,
• upgade,
• upsate,
• epsode,
• epsidoe,
• oudside,
• ourside,
• uprade,
• eposide,
• ibside,
• otside,
• upsale,
• iside,
• itside,
• ouside,
• utside,
• upsite,
• upsode

• upcode,
• upset.

The adjective form of the word "upside" is "upside-down".

The plural of the "upside" can be the "upsides".

The singular of the "upside" can be the "upside".