What is the origin of "Usono"?

Question

What is the origin of the country-name "Usono"? The online Plena Illustrita Vortaro de Esperanto gives the word as Uson-o, so "Uson" is the root. But what is this derived from? At face value, it would seem to be an acronym - USN - u-so-no, but what does that stand for? There seems to be little relation between it and "Unuiĝintaj Ŝtatoj de Ameriko".

Related: Why are country names in Esperanto so "irregular"?

Answer 1

According to Reta Vortaro:

Malgraŭ la impreso kiun oni povas ricevi el PIV, en Esperanto la vorto Usono ne estas mallongigo de la Esperanta vortgrupo „Unuiĝintaj Ŝtatoj de Nord-Ameriko“, sed plenvalora vorto, proponita ekster Esperantujo de usonanoj Frank Lloyd Wright kaj James Duff Law kaj aliaj laŭ la angla vortgrupo „United States of North America“ (en la formo „Usonia“), ĉe la limo inter 19a-20a jc. Ĝi tamen plej firme enradikiĝis en Esperanto.

Translation: Despite the impression one can receive from PIV, in Esperanto the word "Usono" is not an abbreviation of the Esperanto phrase "Unuiĝintaj Ŝtatoj de Nord-Ameriko", but a full-fledged word, proposed outside of the Esperanto community by Americans Frank Lloyd Wright and James Duff Law and others, based on the English phrase "United States of North America" (in the form "Usonia"), at the turn of the 19th to 20th century. It, however, most firmly became rooted in Esperanto.

So in other words, the original abbreviation was USONA (United States of North America), which was adapted to form the English words "Usonia" (meaning "USA") and "Usonian" (meaning "American"). Though originally English, the words never really took off in the English language, but Zamenhof adopted them into Esperanto before they fell into disuse.

On Frank Lloyd Wright's use of "Usonia" see the Wikipedia article.