Origins of the title
was said to be the first President's wife to be referred to as "First Lady" (this was at her funeral in 1849).
The use of the title First Lady to describe the spouse or hostess of an executive began in the United States. In the early days of the republic, there was not a generally accepted title for the wife of the president. Many early first ladies expressed their own preference for how they were addressed, including the use of such titles as "Lady," "Mrs. President" and "Mrs. Presidentress"; Martha Washington was often referred to as "Lady Washington." One of the earliest uses of the term "First Lady" was applied to her in an 1838 newspaper article that appeared in the St. Johnsbury Caledonian, the author, "Mrs. Sigourney", discussing how Martha Washington had not changed, even after her husband George became president. She wrote that "The first lady of the nation still preserved the habits of early life. Indulging in no indolence, she left the pillow at dawn, and after breakfast, retired to her chamber for an hour for the study of the scriptures and devotion".
Dolley Madison was reportedly referred to as "First Lady" in 1849 at her funeral in a eulogy delivered by President Zachary Taylor; however, no written record of this eulogy exists, nor did any of the newspapers of her day refer to her by that title. Sometime after 1849, the title began being used in Washington, D.C., social circles. One of the earliest known written examples comes from November 3, 1863, diary entry of William Howard Russell, in which he referred to gossip about "the First Lady in the Land," referring to Mary Todd Lincoln. The title first gained nationwide recognition in 1877, when newspaper journalist Mary C. Ames referred to Lucy Webb Hayes as "the First Lady of the Land" while reporting on the inauguration of Rutherford B. Hayes. The frequent reporting on Lucy Hayes' activities helped spread use of the title outside Washington. A popular 1911 comedic play about Dolley Madison by playwright Charles Nirdlinger, titled The First Lady in the Land, popularized the title further. By the 1930s, it was in wide use. Use of the title later spread from the United States to other nations.
When Edith Wilson took control of her husband's schedule in 1919 after he had a debilitating stroke, one Republican senator labeled her "the Presidentress who had fulfilled the dream of the suffragettes by changing her title from First Lady to Acting First Man."
The wife of the Vice President of the United States is sometimes referred to as the Second Lady of the United States (SLOTUS), but this title is much less common.
Non-spouses in the role
Several women (at least thirteen) who were not presidents' wives have served as First Lady, as when the president was a bachelor or widower, or when the wife of the president was unable to fulfill the duties of the First Lady herself. In these cases, the position has been filled by a female relative or friend of the president, such as Martha Jefferson Randolph during Jefferson's presidency, Emily Donelson and Sarah Yorke Jackson during Jackson's, Mary Elizabeth (Taylor) Bliss during Taylor's, Mary Harrison McKee during Benjamin Harrison's presidency, upon her mother's death, Harriet Lane during Buchanan's, and Rose Cleveland prior to Cleveland's marriage.