n. 1. [techspeak, primarily UNIX]
The ASCII LF character (0001010), used under UNIX as a text line terminator. A Bell-Labs-ism rather than a Berkeleyism; interestingly (and unusually for UNIX jargon), it is said to have originally been an IBM usage. (Though the term 'newline' appears in ASCII standards, it never caught on in the general computing world before UNIX).
2. More generally, any magic character, character sequence, or operation (like Pascal's writeln procedure) required to terminate a text record or separate lines.