So it comes as something of a surprise to learn that “overwhelm” has been a noun since at least 1596, according to the Oxford English Dictionary. The definition given, “[t]he action of overwhelming; ...

A noun is a word for a person, place, or thing. Find out how you can use them in your writing with this Bitesize Primary KS1 guide.

So if “the reason is” needs a noun to come next, that means “the reason is that” works and “the reason is because” doesn’t. Makes sense, but grammar is never so simple.

Collective nouns are singular in form, “a team,” but refer to a group of two or more people or things. In other words, they’re singular and plural at the same time.