The name Denny has its origins in the Celtic language, deriving from the Gaelic word "denbh," which means "brave" or "bold." It is thought to have first emerged in the early medieval period, around the 5th or 6th century, among the Gaelic-speaking populations of Ireland, Scotland, and parts of Wales.

One of the earliest recorded instances of the name Denny can be found in the Annals of Ulster, an ancient Irish chronicle that dates back to the 15th century. In these annals, there is mention of a man named Denbh mac Conchobhair, who lived in the 12th century and was a member of the ruling dynasty of the Kingdom of Connacht.

Throughout history, the name Denny has been borne by a number of notable individuals. One of the most famous was Dennis the Carthusian (c. 1370-1471), a Flemish monk and theologian who played a significant role in the Catholic Church's response to the Hussite movement in Bohemia.

Another well-known figure was Denny Laine (born 1944), an English singer-songwriter and guitarist who was a founding member of the rock bands The Moody Blues and Wings, the latter of which he co-founded with Paul McCartney.

In the realm of sports, Denny McLain (born 1944) was an American baseball player who won the Cy Young Award in 1968 and was a key member of the Detroit Tigers' World Series championship team that same year.

The name Denny has also been associated with literary figures, such as Denny Bradbury (1923-2016), an American poet and educator who served as the Poet Laureate of Missouri from 1997 to 2003.

Finally, Denny Hamlin (born 1980) is a contemporary NASCAR driver who has won multiple races in the Cup Series and is considered one of the sport's top competitors.

While the name Denny has remained in use throughout the centuries, its popularity has ebbed and flowed over time, reflecting the changing cultural and linguistic landscapes of the regions where it originated and was adopted.