Activity may mean:

• action, generally
• activity (chemistry), the effective concentration of a solute for the purposes of mass action
• activity (radioactivity), the number of disintegrations per second
• activity (project management),
• activity (software engineering).
• activity (soil mechanics)
• in chess, the ability of a piece to influence the game
• the HMS Activity an aircraft carrier of the Royal Navy
• in physical chemistry and enzymology, the rate of a catalytic reaction such as enzyme activity
• an alternative name for the game charades

Aktivität | Activité | Aktywność stężeniowa | Aktivnost | Aktivitet