Adjoint, self-adjoint, Which is the proper noun?

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I'm currently learning linear algebra, and I was confused by these two terminologies.

It seems that adjoint is the tranpose of cofactor matrix, and a self-adjoint operator has a matrix representation whose conjugate tranpose equal to itself.

But I just met a question, that ask me to prove

$$(im~L)^\perp=ker~L^*$$

where $L^*$ is the adjiont of L

It indicates that L*, the adjoint of L, is the conjugate transpose of L.

I wonder whether adjoint has something to do with self-adjoint.

If not, then what's their difference, and how do I tell the difference when digesting the description of any other question.

Thanks in advanced!