FLOTUS (an acronym for ‘First Lady of the United States’), is a slang or jargon term for the wife of an American president, on the model of POTUS (President of the United States) and SCOTUS (Supreme Court of the United States). The latter terms originated in the late 19th century, when they were used as telegraphic abbreviations, and were later revived as insider terminology before passing into more general use. Although the phrase First Lady of the United States is also attested from the 19th century, FLOTUS seems to be much newer; the first evidence thus far found by the OED‘s researchers is from the early 1980s, referring to Nancy Reagan:
To their Secret Service shadows they may be ‘POTUS’ and ‘FLOTUS’, but to each other out on their 688-acre California ranch he’s still her ‘Ronnie’ and she’s still his ‘Nancy’.
1983 Washington Post 20 Sept. c1/1
Was Nancy Reagan the first first lady to be referred to as FLOTUS, or does some other presidential spouse hold that crown? Since the term likely arose among White House insiders, memos and diaries might be good sources of earlier evidence.
Posted by OED_Editor on 23 July 2014 15.10