All of the four terms (Artificial Intelligence, Machine Learning, Data Science and Big Data) are interlinked, but not interchangeable. I guess the following overview would help beginners with easily differentiating them: Everything you need to know about key differences between AI, Data Science, Machine Learning and Big Data (see the article for more details)

• AI focuses on mimicking decision-making processes.
• ML reaches beyond the available pieces of training information and interpret data that has never been encountered before.
• Data science combines various methods and data of diverse volumes in order to derive useful, mostly business-oriented, insights through both structural and predictive analyses.
• Big data doesn’t analyze but focuses on processing (with high velocity) extreme volumes and a wide variety of data types.