interaction

interaction — noun

1. a situation where at least two people have a conversation, do things together, o

1.nounB1
Definition

a situation where at least two people have a conversation, do things together, or react to what others say or do

Example

Tariro enjoys the daily interaction with her colleagues at the office.

interaction with [colleagues/people]

The teacher watched the interaction between the children during the group project.

Common collocations
  • social interaction
  • face-to-face interaction
  • human interaction
  • daily interaction
  • direct interaction
  • peer interaction
Synonyms
  • communication

    broader term covering any exchange of information; does not always imply two-way back-and-forth

  • contact

    suggests a brief or surface-level connection rather than extended mutual engagement

  • exchange

    emphasises a reciprocal giving and receiving, often of specific things like ideas or greetings

Antonyms
  • isolation

    state of being alone or separated from others, with no interaction

Grammar Patterns

interaction between [plural noun]

interaction with [noun]

[adjective] interaction

Usage Note

Commonly uncountable when referring to the general activity of communicating, and countable when describing a specific instance or type (e.g. 'a brief interaction at the door').

Common Mistakes

There is not enough interaction within the team members.
There is not enough interaction between the team members.
use 'between' (not 'within') to name the participants in an interaction.
I had an interaction with my teacher about homework.' (sounds unnatural for a one-sided or brief exchange)
I spoke with my teacher about the homework assignment.
'interaction' implies two-way mutual engagement, not a simple question-and-answer.

2. a situation in which two or more things, forces, or processes affect or influenc

2.nounB2
Definition

a situation in which two or more things, forces, or processes affect or influence each other

Example

The interaction between the two drugs caused unexpected side effects in some patients.

drug interaction — common collocation in medicine

Scientists are studying the interaction of sunlight with ocean algae.

interaction of [X] with [Y]

Common collocations
  • drug interaction
  • chemical interaction
  • complex interaction
  • interaction effect
  • environmental interaction
  • genetic interaction
Synonyms
  • interplay

    more literary or formal; suggests a dynamic or intricate mutual influence

  • reciprocal effect

    emphasises the two-way nature of the influence; more technical in tone

  • mutual influence

    a direct synonym, often used in social sciences and physics

Antonyms

Grammar Patterns

interaction between [plural noun]

interaction of [noun] with [noun]

interaction among [plural noun]

Usage Note

Common in scientific, technical, and academic writing. When used about medicines or chemicals, it often implies an unwanted or surprising effect that does not happen with either substance alone.

Common Mistakes

The interaction between the medicine is dangerous.
The interaction between the two medicines is dangerous.
name both participants in the interaction; a single thing cannot interact with itself.

Word family

Synonym discussion

Sense: noun/1

All four words describe connections between people, but each highlights a different aspect. Communication is the broadest term — it covers any transmission of information, whether one-way or two-way, verbal or non-verbal. Interaction adds the idea of mutual action and reaction: both sides influence each other, not just send messages. Contact often suggests a brief or surface-level connection, such as eye contact or a quick phone call, rather than sustained mutual engagement. Exchange emphasises reciprocity — a giving and receiving of specific things such as ideas, gifts, or words. Dialogue specifically means spoken conversation between two or more people, usually with the aim of sharing perspectives or reaching understanding. To illustrate: reading a notice board involves communication but little interaction; a friendly chat between colleagues during lunch involves both interaction and dialogue; a handshake at a meeting is a brief contact.

communication ↗contact ↗exchange ↗dialogue ↗

Common collocations

Nouns

Adverbs

Phrases

  • in interaction with
  • through interaction
  • pattern of interaction

Prepositions

Etymology

LatinEnglish

The word 'interaction' was formed in English in the early 1800s by joining the prefix 'inter-', meaning 'between or among' (from Latin), with 'action', from Latin 'actio' meaning 'a doing, a putting in motion'. The core idea is 'action between' — a fitting origin for a word that describes how people or things act upon each other.