Adjectives

(a)identical, monovular(of twins) derived from a single egg or ovum“identical twins are monovular”
(s)identical, indistinguishableexactly alike; incapable of being perceived as different“rows of identical houses”, “cars identical except for their license plates”, “they wore indistinguishable hats”
(s)identical, selfsame, verybeing the exact same one; not any other:“this is the identical room we stayed in before”, “saw the selfsame quotation in two newspapers”, “on this very spot”, “the very thing he said yesterday”, “the very man I want to see”
(s)identicalhaving properties with uniform values along all axes
(s)identical, superposablecoinciding exactly when superimposed“identical triangles”