Unspecified or unknown (unlocated) place or location.
"I left my keys somewhere in the house, but I can't remember which room they are in."
In plain English: A somewhere is a specific place where you can go or be located.
"I will keep the book somewhere safe until you need it."
Usage: Use this noun to refer vaguely to an unspecified destination, such as in the phrase "go somewhere." It is often confused with the adverbial form when speakers mistakenly try to specify a concrete location rather than indicating general direction.
In an uncertain or unspecified location.
"I can't say exactly where I left my keys, but they must be somewhere in the house."
In plain English: Somewhere is an indefinite place that you are going to or where something is located, but you don't know exactly which one it is.
"We need to find somewhere quiet to have our meeting."
The word somewhere is a compound formed by combining the words some and where. It entered English as a straightforward combination of these two existing terms to indicate an unspecified place.