What is topline?
The melody and lyrics written over an existing instrumental. Topline writers work fast against a finished track, which is exactly the situation where memorising a brand-new lyric is unrealistic.
Sessions like these commonly record a demo vocal within an hour of the words being written, so a readable prompt is the difference between capturing the idea and losing it.
The most memorable part of a song — often the title line, sung at the point the listener is most likely to remember it. Hooks are usually short, repeated, and built from plain, concrete language.
A rough vocal recorded as a reference for arranging and editing, not intended for release. Scratch takes are usually cut quickly, often by the writer, and often before the lyric is finished.