Messrs Hoover, Biro, Sandwich, and associates
Every so often, when I say I'll do the hoovering, someone - we could call them a wit or a pedant, depending on my mood that day - will say, "Actually, it's not a Hoover: it's a Henry."
Fine! Yes, it's a vacuum cleaner. I could say I'll do the vacuuming, but that feels more 1950s housewife than I am comfortable with. Hoover really won the brand war. They were actually invented by a chap called Spangler but Mr Hoover developed and sold them. So there's an alternate universe not too many branches away where I say I'll do the spangling.
László Bíró didn't even invent the ballpoint pen. There are patents fifty years older than his. But he did it better and his is the name that stuck. I know it's a ballpoint pen but I would never call it that. It's just a biro.
I try not to use google as a verb because I don't actually google. The problem is 'search' could be any kind of searching, not necessarily online. And if I said 'web-search' I'd sound like a newsreader trying to explain the internet back when it was a niche hobby rather than the backbone of civilisation. So sometimes I have to accept this in order not to sound like an alien failing in my disguise.
Sellotape is a brand name. What would we call the stuff? Wikipedia describes it as 'transparent, cellulose-based, pressure-sensitive adhesive tape'. Imagine saying that when you are wrapping presents. Velcro is also a brand name. Again, what would we say? 'Hook-and-loop fastener'? I'd sound like a trademark lawyer. Frisbee and Thermos are brand names but also the only sensible thing to call the thing itself. Zipper and escalator became so ubiquitous as terms they actually lost their trademarking.
This process is apparently called genericide, or slightly less terrifyingly, genericisation - and it's an actual problem for trademark owners trying to hang on to their rights. It is of course very local. This post probably sounds painfully British because all countries will have their own versions.
Then there are eponyms. No trademarks here, just an inventor or popularising aristocrat whose name got attached.
The story goes that the Earl of Sandwich wanted to eat meat and play cards at the same time, thus had his meat brought out in bread. Using bread as a plate was not uncommon. There were already 'meals encased in carbs' like pastries. So not a huge jump. Now anything can be sandwiched between anything else - it's just a word.
A hybrid case: Tarmac is properly tar-bound macadam. Mr McAdam came up with the idea of using crushed rock for roads. Sometimes you'll see it mentioned in books - one of the fancy new macadamised roads, eh. Then, with increasing traffic, tar was used to stop it getting dusty and falling apart. This was then patented in 1903 by a completely different person, Edgar Purnell Hooley. Because I don't know anything about the civil engineering of it, I'll use 'tarmac' to refer to most anything road-like.
For some time I was confused about why the French call hot air balloons montgolfières - it is of course because they were invented by the Montgolfier brothers. Patiently waiting for that to come up on a quiz.
Then there's Thomas Crapper, a famous plumber and inventor of toilet-related innovations such as the U-bend and ballcock, and provider of crappers to the crown. Crap wasn't even named after him but the joke got out of hand. Ignominy.
Next time this comes up, depending on whether I'm feeling like a wit or a pedant, I'll tell them about the spangling, or lecture them on linguistic drift.
Wikipedia has a list of generic and genericised trademarks that is good fun to peruse.