What programming operation is defined as joining strings together?

The operation defined as joining strings together is known as concatenation. In programming, concatenation refers to the process of appending one string to the end of another, creating a new string that combines both. For example, if you have the strings "Hello" and "World," concatenating them would result in "HelloWorld." This operation is fundamental in many programming languages and is often performed using specific operators or functions designed for string manipulation.

Other options like segmentation refer to dividing data into smaller parts, compiling involves translating code into executable form, and distribution typically pertains to the deployment of software, none of which pertain to the act of joining strings. Therefore, concatenation is the precise term used for the operation of merging two or more strings.