A ‘top and tail’ is a cut of the jingle where there is sung vocals at the start, no sung vocals in the middle (just the instruments playing) and then sung vocals at the end. This is a very popular format in the radio and television industry as it allows a spoken message (voice over) to be heard over the instrumental part.
A top and tail typically sounds like this:
Music is played right from the start. The name of a business or product is sung for a few seconds. The music then goes a bit quieter and a spoken voice enters, describing a sale, a deal or a general message. The music picks up again right at the end and the singing is heard again (usually the same as the start). This is a top and tail.
For more definitions, read the post jingle lingo, what does it all mean.