It is the term used for the models runway, although it is probably true that it is also a name for the narrow walkway that which a cat tip toes across, I personally think it has a double meaning. Those models are usually hissing and scratching like cats at each other at fashion shows....hence cat walk.Meow.
A catwalk is commonly referred to the narrow strip that models walk down. It comes from narrow passes that cats have the ability to cross very gracefully and with good balance.
When your at something, like a fashion show and the people that's modeling is on the stage modeling and showing off clothes, they actually refer the stage to being the "Catwalk"!
Walks that cat's do, The catwalk, some do it slow some do it chasing things and some do it very carefully. Some also do it when they are covering up their poop!!!!
"Strutting Pussycats" walkway...is what's alluded to ;-)