Question

The first Americanized short version of this word, deli, came into existence ca. 1954.

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How do you read "ca."?
It is short for "circa" according to a dictionary.
And 'circa' means 'about'.

Answer 1

Yes, and you can either say, "… about 1954" or "circa 1954" (although more people will understand the former than the latter!).