twin

[1]	pair , match , yoke , join , link , couple , combine , connect , associate
[2]	duplicate , parallel
[3]	match , mate , couple , pair

[1]	double , clone , duplicate , look-alike , counterpart , (Slang) ringer
[2]	Gemini
[3]	Twin Falls
[4]	counterpart , similitude

adj.

[1]	identical , matching , matched , duplicate , corresponding , look-alike
[2]	duplicate , matching , twinned