What is the definition of a literature study? and what is the definition of empirical research?i want to know the definition of both literature...

A literature study is also referred to a literature review.  When you embark upon a research project, the idea is that your research should not take place in a vacuum, without any reference to the research of others in your content area and topic. Your research should be rest upon the shoulders of those who have gone before you, within the context of the research of others. 

You are expected to review the work of others in your content area and subject, and write about the results of your review. This serves several purposes. First, this enables you to understand more fully the theories that your own research might rest upon and immerse yourself in the language of your discipline. Second, it allows you to justify the need for your own research. You might find out that what you propose to research has already been studied extensively, and you are not making any contribution to the world's knowledge if you follow a particular path. When this happens, you have a good foundation with which to think about what else you might research, a need in the discipline for further knowledge. Third, your review allows your reader to have a contextual backdrop to your research, a way of fitting what you have to present into the big picture. 

Empirical research is the research that you conduct through observation or experiment.  There are many kinds of empirical research, both quantitative and qualitative.  For example, empirical research might consist solely of a teacher observing a classroom and making detailed notes about the students, or it might consist of an anthropologist observing the behavior of the people in a particular tribe. Empirical research might involve counting how many cars pass a particular intersection or finding out how many sexually abused people in a given community are drug users. 

Generally, a formal paper will begin with an introduction, move on to a review of the literature and then move on to a discussion of your research, its rationale, methodology, and results, followed by the conclusions that you may draw from those results.  Sometimes schools have their own conventions or template for how this is done, so it is always best to find out the school's requirements and have a look at sample papers from your school.