activity

noun (plural activities)

• 1the condition in which things are happening or being done:there has been a sustained level of activity in the economy 16, they say, is too young for sexual activity
• busy or vigorous action or movement:the room was a hive of activity

• 2 (usually activities) a thing that a person or group does or has done:the firm’s marketing activities
• a recreational pursuit or pastime:a range of sports activities
• (activities) actions taken by a group in order to achieve their aims:the police were investigating anarchist activities

• 3the degree to which something displays its characteristic property or behavior:abnormal liver enzyme activities
• Chemistry a thermodynamic quantity representing the effective concentration of a particular component in a solution or other system, equal to its concentration multiplied by an activity coefficient.