Definitions:

1. Describes a situation where two or more items, entities, or conditions are indistinguishable from each other in all aspects. NOUN
   • The identicalness of the replicated artifact made it indistinguishable from the original.
2. Refers to the state or condition of being exactly the same in every way. NOUN
   • The identicalness of the twins made it difficult for their teachers to tell them apart.

Synonyms:

• equivalence
• exactness
• Sameness
• uniformity