Definition

1. Noun:
   • The state or quality of being active; the ability to move or function with energy and vigor: This refers to the general trait of not being idle or passive.
   • A specific action, pursuit, or function; something that a person or group does: This refers to a particular task, hobby, or operation.
   • A natural process or occurrence: This refers to actions or changes that happen in the natural world without human design.
   • (Chemistry) The degree to which a substance participates in a chemical reaction: This is a technical measure of a substance's reactivity.
   • (Physics) The intensity of a radioactive source: This is a technical measure of radioactive decay events per unit time.

Examples of Usage

• Noun:
  • The children's high level of activity made the classroom noisy. (Referring to the state of being energetic.)
  • Reading is her favorite leisure activity. (Referring to a specific pursuit.)
  • Seismic activity has increased in the region. (Referring to a natural process.)
  • The catalyst increases the activity of the reaction. (Referring to a chemical property.)
  • The lab measured the activity of the radioactive sample. (Referring to a physical property.)

Advanced Usage

• "be in activity": to be in operation or actively happening.
  • The volcano is currently in activity.
• "sphere of activity": the area or scope within which someone or something operates.
  • Her main sphere of activity is biomedical research.

Variants and Related Words

• Active (adj): engaged in action or characterized by energetic work; functioning.
  • He leads an active lifestyle.
• Activate (verb): to make active or more active; to set in motion.
  • Press the button to activate the system.
• Activism (noun): the policy or action of using vigorous campaigning to bring about political or social change.
  • She is known for her environmental activism.

Synonyms

• Action: the process of doing something.
• Movement: the act or process of moving.
• Operation: the fact or condition of functioning or being active.
• Pursuit: an activity that one engages in.

Related Phrases

• Extracurricular activity: an activity pursued outside one's regular academic coursework.
  • Debate club is a popular extracurricular activity.
• Commercial activity: business or trade operations.
  • The new port increased commercial activity in the town.

Related Idioms

• A hive of activity: a place where many people are busy doing things.
  • The kitchen was a hive of activity before the party.
• Burst into activity: to suddenly start being very busy or active.
  • The office burst into activity after the announcement.

Noun

1. the trait of being active; moving or acting rapidly and energetically
   • the level of activity declines with age
2. a process existing in or produced by nature (rather than by the intent of human beings)
   • the action of natural forces
   • volcanic activity
3. (chemistry) the capacity of a substance to take part in a chemical reaction
   • catalytic activity
4. an organic process that takes place in the body
   • respiratory activity
5. the state of being active
   • his sphere of activity
   • he is out of action
6. any specific behavior
   • they avoided all recreational activity