I would like to know whether these phrases "English Department" and "Department of English" have the same meaning. Thanks!
One difference may be that if you say english department, you may add to that. This would imply that the department is part of a wider range. You could say "This is the English department of the univesity" which would definitize the existence of other departments within that university. However, if you were to say "This is the department of English" there may or may not be other departments.
I hope that this helps ;)