I recently bought an iPad, and various people have been recommending apps to me. One of the most popular is Shazam. Funnily enough, I heard the word shazam during Andrew Marr's programme on Sir Walter Scott, which I blogged on recently (here). Marr said 'the full shazam' when talking about the Edinburgh monument to Robert Burns, which isn't quite as ornate as the one to Sir Walter Scott, or isn't 'the full shazam'. This is a Marr-ism; it's not a common English idiom (Andrew Marr is Scottish).
The OED says that shazam is a children's slang word, an invented word like ‘abracadabra’ or ‘presto’ to introduce an extraordinary deed or story. The word did not feature in Stephen Fry's programme on the language of magic, the subject of my previous post, but I suppose it has the same exotic qualities - unlike any other English word and containing a Z, one of the rarest letters in English. Shazam was originally the wizard's name in the Captain Marvel superhero stories (and Captain Marvel's alter ego? - I'm finding the information I read on this very confusing, so apologies if I've got the facts wrong). Supposedly, Shazam is an acronym, made up of the initials of the six powerful mythological figures Solomon, Hercules, Atlas, Zeus, Achilles and Mercury.