Certain | Mean of certain in English Dictionary

/ˈsɚtn̩/

• not having any doubt about something
1. Are you certain [=sure] you want to leave today?
2. I feel less than certain about it. [=I am not sure about it]
3. She's certain (that) she can do the job despite her lack of experience.
4. I'm fairly certain that I'll be on time.
• without a doubt
1. No one knows for certain what the outcome will be.
2. We'll need more than an hour to get there for certain. [=for sure]
• to do something or find out something so that you have no doubt about whether something is true, correct, will happen, etc.
1. Make certain (that) you lock the door when you leave. = Make certain to lock the door when you leave.
2. We must make certain [=make sure] this doesn't happen again.
3. She made certain she thanked each of them for coming.
4. Make certain of your flight times [=be sure that you definitely know your flight times] before you leave for the airport.

• certain ones
1. Certain of his assumptions are simply not true.
2. We know that certain of his classmates walk to school every day.