The name Kennie is a Scottish variant of the given name Kenneth, which has its origins in the Gaelic language. The name is derived from the Celtic elements "ced" meaning "fire" and "nath" meaning "born" or "chieftain." Together, these elements form the meaning "born of fire" or "chief born."

The name Kenneth has a long history, with its earliest recorded use dating back to the 6th century AD. It was particularly popular among the Picts, an ancient Celtic people who lived in what is now eastern and northern Scotland. The name was later adopted by Scottish clans, and it became associated with royalty and nobility.

One of the earliest recorded instances of the name Kenneth is in the "Book of Deer," a 9th-century Latin manuscript containing the oldest surviving Gaelic writing. The manuscript mentions a Pictish king named Kenneth, believed to be Kenneth I, who reigned over the Kingdom of Alba (ancient Scotland) in the mid-9th century.

Throughout the Middle Ages, the name Kenneth was borne by several Scottish kings and nobles. One notable figure was Kenneth III, who ruled as King of Scots from 997 to 1005 AD. He was responsible for bringing the relics of St. Columba to the church in Dunkeld, which became a significant religious center in Scotland.

Another famous bearer of the name was Kenneth MacAlpin, who is credited with being the first king to unite the Picts and the Gaels into the Kingdom of Alba in the 9th century. He is considered a pivotal figure in Scottish history and the founder of the royal line that would eventually become the House of Stuart.

In the 12th century, the name Kenneth was also present in Ireland, where it was anglicized as "Kennie." One notable Irish bearer of the name was Kennie O'Clery, a 17th-century historian and chronicler who was part of the famous O'Clery family of scholars and scribes.

The name Kennie has also been used in literature and popular culture. One example is Kennie Lazzari, a character in the novel "The World According to Garp" by John Irving, published in 1978.

While the name Kenneth has maintained its popularity throughout the centuries, the variant spelling "Kennie" is less common today. However, it remains a testament to the rich cultural heritage and historical significance of this name, which has its roots in the ancient Celtic traditions of Scotland and Ireland.