What is the meaning of “fat”? That’s easy, you say. There’s full-fat and there’s half-fat, and there’s fat as a feminist issue. But what is the meaning of “phatt”?

I discovered phatt one Sunday evening as I was fiddling with my car radio, and gate-crashed Radio 1‘s weekly programme of dance anthems.

I can’t remember when I last set foot inside a club. But this high-speed, synthesised music seemed made for night-driving. Was it hip-hop or trip-hop, acid jazz or swing beat? Perhaps it was techno-trance. Never mind. It choreographed the swooping lights and brought the flickering crash barrier to life. It was go-faster music.

And I clearly wasn’t the only motorway listener. Every so often, the radio presenter would interrupt a track to take a phone call from a car-load of fans. They spoke a weird argot, these student hedonists from the once-industrial cities. “A big shout-out to all my mates at uni,” they would say, breaking into shrieks. “It was a banging session at the Polka Dot on Friday. Massive!” Frequently, they would end with, “Roll us afat one!” This, I assumed, was the cannabis talking.

Likewise, when I heard “fat” in lyrics and track titles, I thought little of it, until one day I saw “phatt” written on the back of a CD cover. Was I missing something?

My dictionary of slang was totally phatt-free. Could the Internet help? Here was an advert for “a 16-part multi-timbral electronic sample player”. It was made by a Californian company called E-Mu, and it’s name was Planet Phatt.

Did the buck stop with the machine that made the music? Was PHATT an acronym for Polyphonic Harmonising Analogue Thyristor Technology, or something similar? “Afraid not,” said the man at E-Mu. “Fat goes way back in hip-hop. In the same way that ‘bad’ is good, fat is something that’s really good. It’s got all the features. It’s the dog’s bollocks.”

He took me back to the early Eighties and led me through the streets of Los Angeles, showed me graffiti on the subway - even explained how fat begat fatt and fatt became phatt.

Yet again I had glimpsed a world in a word. And to think I might have missed it in a blink.