What is difference between market research and marketing research?

Marketing Research is research aimed at gathering information on all aspects of marketing. The purpose is to enhance an organisation's marketing processes and activities. As such it includes aspects such as advertising research (i.e. research looking at the effectiveness of advertising), sales research (e.g. research to look at the best sales approaches), channel research, competitor research, etc.

In contrast, Market Research focuses on markets i.e. the customer or prospective customer. As a result (unless it is used as a synonym for marketing research), it won't look at aspects such as advertising effectiveness research. The focus is strictly on the market itself. It may include some sales research studies and competitor studies - in as much as these can also look at customer/prospect responses.