To "concatenate" means to link or join together. In computing and programming, it often refers to combining strings of text into a single string. For example, if you have the strings "Hello" and "World," concatenating them would result in "HelloWorld." This process is commonly used in various programming languages, such as Python and Java. Concatenation can also apply to other data types, such as lists or arrays. When you concatenate lists, you create a new list that contains all the elements from the original lists in the order they were added. This technique is useful for organizing and managing data efficiently.