Certain: meaning, definitions and examples

Used when you are very sure about something or when there is no doubt.

• She is certain that she left her keys on the table.
• It is certain that the sun will rise tomorrow.

Used when you feel very certain about something, often informally.

• Are you sure you want to do this?
• I'm sure everything will work out.

Used to describe a feeling of self-assurance, typically arising from one's appreciation of their own abilities or qualities.

• He is confident that he will pass the exam.
• She spoke in a confident manner during the presentation.

Used when you have been persuaded or have a strong belief in the truth of something, often after hearing or seeing evidence.

• She was convinced by the evidence presented at the trial.
• I'm convinced that he's telling the truth.

There is a specific, but unnamed, person or thing.

• A certain someone left you a message.
• She lives in a certain part of the city.

Used when referring to something clearly defined or identified. Often related to details or precise information.

• I need specific instructions to complete the task.
• She asked for a specific type of book.

Used to single out an individual item or detail from others. Can imply a higher level of specificity or attention to detail.

• She has a particular way of handling things.
• Is there any particular reason you’re asking?

Used when something is clearly defined and not vague. Stronger than 'certain' in expressing exactness and clarity.

• We need a definite answer by tomorrow.
• There was a definite change in his attitude.