Argthtjtr

I googled the words "to sock away" and came up with definitions aplenty, but no reference to the phrase's origin. Surprisingly, at least to me, was the suggestion, from Oxford, that it was a North American usage. The Free Dictionary adds New Zealand to that small cluster.

I tried to imagine people hiding their money in a sock, either worn or hidden somewhere else. What else to do with a single sock, once its partner has skipped town? Then I remembered that Norwegian has the term "å sokke bort" which seems remarkably similar.

This information wasn't completely satisfying. Why not just "sock it" or "put in a sock"? And did the Norwegians get it from English or vice versa? Or has it spread from/to elsewhere?

I don't know if it is just me, but the idea of socking something away does not sound like a gentle motion. Perhaps with a little sleight of hand - so everyone doesn't know where you've put it. That makes me wonder if it is related to "socking s.o" as in "I socked him in the eye". It really forces me to think that this has nothing at all to do with socks.

OED first attests 'sock' ("also with away", colloquial, "orig[inally] U.S.") in the sense of "put (money) aside as savings" in 1942, and Etymology Online echoes that date for the sense. Etymology Online speculates that the phrase arose "from the notion of hiding one's money in a sock".

A newspaper search finds two mentions of hiding or stashing money in a sock in 1891. The Austin American-Statesman (Austin, Texas) of 17 May 1891, page 2 (paywalled), mentions the proverbial sock in a blurb:

It is said there are about $2,100,00 left jingling about in the toe of Bill Wortham's old sock away back in the corner of the vault.

The Atlanta Constitution (Atlanta, Georgia) 26 Jul 1891, page 21 (paywalled), records a mention of the practice in a speech:

I would rather get my pocket change from an old sock hid away under my own roof, than to give it in order that those other fellows might grow fat.

In 1893, a colloquial use of the verb phrase, with "away", appears in story dialog on page 2 of the 25 Sep Detroit Free Press (Detroit, Michigan; paywalled):

"Anything more than a million is vexation of spirit. I'd just sock that away and cover up sins with the rest."

While not strictly evidence that the use of the verb in the given sense arose from the practice of hiding or keeping money in a sock, the mentions of the practice followed by the appearance of the verbal sense do suggest that origin.