Read the dictionary definition of twin. All definitions for this word.
1. a duplicate copy
2. a waterfall in the Snake River in southern Idaho
3. (astrology) a person who is born while the sun is in Gemini
4. either of two offspring born at the same time from the same pregnancy
5. give birth to twins
6. grow as twins
1. twin crystals
7. bring two objects, ideas, or people together
1. This fact is coupled to the other one
2. Matchmaker, can you match my daughter with a nice young man?
3. The student was paired with a partner for collaboration on the project
8. duplicate or match
1. The polished surface twinned his face and chest in reverse
9. being two identical
See also: Merriam-Webster definition of twin