1. an unknown and unexplored region;
2. anyone who does not belong in the environment in which they are found
3. a variable whose values are solutions of an equation
- synonym： unknown quantity
1. not known;
- "an unknown amount"
- "an unknown island"
- "an unknown writer"
- "an unknown source"
- antonym： known
2. being or having an unknown or unnamed source;
3. not known to exist;
- "things obscurely felt surged up from unsuspected depths in her"- Edith Wharton
4. not famous or acclaimed;
5. not known before;
- "used many strange words"
- "saw many strange faces in the crowd"
- "don't let anyone unknown into the house"
- synonym： strange