13th Century: The word originally appeared as singularite in Old French and singularitās in Late Latin. At this time, it meant "unusual or exceptional behavior" or "a being alone".

14th Century: By the mid-1300s, the term evolved to describe "singleness of aim or purpose" or devotion to a single thing. By the late 1300s, it referred to "individual or particular things".

1500s: It began to be used more broadly to describe the "fact of being different from others".

Transition to Scientific and Technical Usage

The word's meaning shifted toward specialized fields in later centuries:

Mathematics (1893): It was first used to describe a point where a function takes an infinite value or becomes undefined.

Physics/Astrophysics (1965): The term was adopted to describe a point of infinite mass density, such as at the center of a black hole.

Technological Singularity (1950s–1990s): Mathematician John von Neumann first used the term in the 1950s to describe a threshold in human affairs beyond which progress is too rapid to understand. It was later popularized in the context of AI by author Vernor Vinge in 1983 and 1993.

(http://www.autoadmit.com/thread.php?thread_id=5824915&forum_id=2#49608036)