Decent point, but most people familiar with metric would work with smaller units than metres and for those unfamiliar with metric, describing it as a billionth of a yard would still sound like a pretty peculiar.

I think describing it as a minute fraction of an inch or centimetre would still be pretty accessible without having to get people to visualize a nanometre.

Right, I thought the usual layperson speak was to compare it to the thickness of human hair or a spider web.