The word 'evaluation' can have slightly different meanings, depending upon the context in which it's used.
However, since you've posted in the 'Jobs & Education' section, I assume that you're referring to an evaluation of staff performance.
In which case, it means much the same as an 'appraisal' or 'assessment'. (If the word is used in it's proper sense, the employee's performance would be given a numerical value, e.g. a score out of 10, but many employers use the word far more loosely and just produce a 'report' rather than an actual 'score').
Chris