[Idiom] thousands upon thousands

[yuriya]

Thousands upon thousands of people lived in the rubble like rats.

Is this (thousands upon thousands) an idiom or just an extension of the preposition upon as in something is heaped upon something else? Thanks in advance!

 

[SoothingDave]

Not a teacher.

It's idiomatic.

 

[BobK]

Is this (thousands upon thousands) an idiom or just an extension of the preposition upon as in something is heaped upon something else? Thanks in advance!

Both. As SD says, it's just idiomatic now, but the phrase was first coined by using the usual preposition sense of 'upon'. ;-)

b

 

[Heterological]

In addition to what others have said, it's worth noting that "thousands upon thousands" is not the only variant of this expression. I've also heard "hundreds upon thousands," "millions upon millions," etc. Curiously, I've noticed that the numbers are either the same, or the first is smaller; i.e. "hundreds upon thousands," or "thousands upon thousands," but never "thousands upon hundreds."