Hermitian Adjoint
In mathematics, specifically in functional analysis, each linear operator on a Hilbert space has a corresponding adjoint operator. Adjoints of operators generalize conjugate transposes of square matrices to (possibly) infinite-dimensional situations. If one thinks of operators on a Hilbert space as "generalized complex numbers", then the adjoint of an operator plays the role of the complex conjugate of a complex number.
The adjoint of an operator A is also sometimes called the Hermitian conjugate (after Charles Hermite) of A and is denoted by A* or A† (the latter especially when used in conjunction with the bra-ket notation).
Read more about Hermitian Adjoint: Definition For Bounded Operators, Properties, Hermitian Operators, Adjoints of Unbounded Operators, Adjoints of Antilinear Operators, Other Adjoints