From The Art and Popular Culture Encyclopedia
A record sleeve is the outer covering of a vinyl recording. The sleeve is technically the paper covering that is closest in contact to the surface of the recording, as in "dust sleeve", "liner" and "album liner". The term has come to be synonymous with "record jacket" and "album jacket", which is the outermost cardboard covering of a vinyl LP. The vinyl LP jacket and the 7"/12" sleeve are the areas to receive considerable attention to graphic design, and will contain the most important and pertinent information about the recording (manufacturer, artist, title of recording, and contents), assuming there is no visible record label with such information. The term "album liner" (or "record liner") led to the expression "liner notes".