A string is a sequence of characters used in programming and computer science to represent text. It can include letters, numbers, symbols, and spaces. Strings are often enclosed in quotes, such as "Hello, World!" or '12345', to distinguish them from other data types. In many programming languages, strings are versatile and can be manipulated through various operations, such as concatenation, slicing, and searching. They are fundamental in tasks like displaying messages, processing user input, and handling data. Common programming languages that utilize strings include Python, Java, and JavaScript.