Data is information such as facts and numbers used to analyze something or make decisions. Computer data is information in a form that can be processed by a computer.
Data is the plural of Latin datum "something given." In scientific use, the word data is often considered to be a plural noun meaning "pieces of information": The data are reliable. But most people think of data as a mass noun meaning "information" and use the word with a singular verb and pronoun: The data is reliable because it was tested by experts.