[TeMPOraL]

> X-Acto knives are a specific type of knives, builder's or craftsman's, not chef's.

Right, but that's still a quite large and generic product category, produced by many manufacturers and sold by many vendors - while "X-Acto" is a specific US brand of a specific US company.

> Equally, a Bic is not any ball pen at all, but a specific inexpensive, usually faceted kind, AFAICT.

Yeah, here we didn't call random ballpoint pens "Bic" - the name was used to refer to only to the specific brand of cheap and shitty orange pens that were easy to find anywhere and which no one wanted to use.

> Xerox, on the other hand, were the original inventors of the particular photocopy process.

Here it's long been a verb. You don't copy documents, you xero documents.