The reverse lyric search window allows you to find all songs that contain a certain word or phrase, in essence the opposite of the program's normal function.
To open the reverse lyric search window, press ⌘R or click Lyric > "Reverse lyric search...".
To use the window, simply start typing text into the search field, and a list of matching lyrics will be updated as you type. Click a result to view the complete lyrics.
Lyricus needs an index of your lyrics to be able to search, and will ask you to create an index the first time you open the window. You can also update the index manually by pressing ⇧⌘R or clicking Lyric > "Update reverse search index".
Lyricus will warn you when your index hasn't been updated in the last week. To remove this reminder, see Preferences.
Please note that the index is only used for the reverse lyric search. No index is necessary nor used in the main lyric display window.