There's a pet peeve that I encounter often while reading advertisements and business names. It's the deletion of plural forms of words.
For example, today I noticed a place called something like "Purcell Tractor and Equipment". Equipment is plural (I'm assuming), but tractor is left as singular. Why isn't it called "Purcell Tractors and Equipment"?
Some places would go as far as to call themselves simply "Purcell Tractor", though that's less common.
So my question is, what is the reason or possible history for leaving words as singular in commercial and formal names? Is there a rule for when to do this? I'm sure there's a major company with a name like this, but an example escapes me.