What is identity?

Identity refers to the inseparable connection between contradictory opposites, and it is the tendency of mutual connection, mutual attraction and mutual penetration between opposites. Identity means that two or more things can coexist and have the same nature.

in bioinformatics, identity refers to the proportion of two sequences with exactly the same nucleotide or amino acid residues at the same site.

Extended data:

There are no two identical concepts in the concept system of formal logic, so there is no relationship between concepts that can realize "identity substitution". However, in the daily language with low accuracy requirements, there are indeed some cases of mixing adjacent concepts, which can only be regarded as the approximate strategy and method of "rounding" in mathematics. If we establish the so-called "replaceable identity" logic operation principle based on this situation, we will inevitably get into trouble.

reference materials? Baidu encyclopedia-identity