1.Definition: (of twins) derived from a single egg or ovum
"Identical twins are monovular"
2.Definition: being the exact same one; not any other:
"This is the identical room we stayed in before"
3.Definition: coinciding exactly when superimposed
4.Definition: exactly alike; incapable of being perceived as different
"Rows of identical houses", "Cars identical except for their license plates"
5.Definition: having properties with uniform values along all axes