Incorrect spelling, explanation: this form is incorrect because salary should be spelled with a, not e; just like its origins (Anglo-French salarie). Salery is thus an incorrect form and salary is the correct one. Salary is the right spelling as two a’s come from its origin.

Correct spelling, explanation: salary spelling goes back to Anglo-French salarie, which is derived from Latin salarium. Therefore it should be spelled with a not e. This means that salery is a mistaken form. The correct spelling is salary.

Definition of salary:
noun, money paid for work, usually monthly
I’ve heard Mike’s salary is poor, but he gets by.
My salary has gotten much better since I changed the department.