Application (or app): A program that reads and displays a PDF or ChordPro file

Console: A functionality of ForScore and OnSong that allows you to edit your song files in a browser window from your PC.

ChordPro: A markup language that identifies the differences between chords, choruses, bridges, etc to allow a program to display a lead sheet correctly on screen.

Filk: The folk music community of science-fiction and fantasy fandom. Yes, I am a part of that fandom.

Markup language: a system for annotating a document in a way that is syntactically distinguishable from the text,[1] meaning when the document is processed for display, the markup language is not shown, and is only used to format the text. HTML and ChordPro are markup languages.

PDF: a file format developed by Adobe in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. PDF was standardized as ISO 32000 in 2008, and no longer requires any royalties for its implementation.

Platform: the hardware/OS combination that is used. Here, we are generally referring to either the Android or iOS platforms.