Definitions of Twin:

• noun:   a waterfall in the Snake River in southern Idaho
• noun:   either of two offspring born at the same time from the same pregnancy
• noun:   (astrology) a person who is born while the sun in in Gemini
• noun:   a duplicate copy
• verb:   grow as twins

  Example: "Twin crystals"

• verb:   duplicate or match

  Example: "The polished surface twinned his face and chest in reverse"

• verb:   give birth to twins
• verb:   bring two objects, ideas, or people together
• adjective:   very similar