It should be no surprise that the word bagel comes from the Yiddish beygel. Ultimately, it’s a diminutive of the Middle High German boug-, meaning ring or bracelet. So a bagel is a “little ring.”
The following translation of Sholom Aleichem’s The Immigrant in America was published in the 2 January 1916 Fort Wayne, Indiana Journal-Gazette:
Once, when I was visiting my brother Elihu, he caught me treating myself to a bagel, which is a kind of pretzel. The bagel was a fresh one, warm, just out of the oven.
There is this from Shmarya Levin’s 1929 Childhood in Exile:
It was a difficult and thankless profession, but Cherneh could not raise the price for fear of competition on the part of the bakers of beigle, or doughnuts. It was generally conceded that though the pancake was heavier and more satisfying, the beigle was daintier and sweeter: it was therefore impossible to give either of them the advantage of price.
The word seems to have become fully Anglicized by the 1930s. From the New York Times of 14 September 1930:
NEW INCORPORATIONS...Hollywood Bagel Baking Co., Newark, general bakery—Herman B. J. Weckstein, Newark.
Copyright 1997-2013, by David Wilton