According to Nolan Warden, whose well-researched article "The History of the Conga Drum" appeared in the February 2005 edition of Percussive Notes (a publication of the Percussive Arts Society): what North Americans call conga drums are actually "tumbadoras."
The origin of the word "conga" is disputed; it may be derived from the Bantu word nkonga meaning "navel" or "umbilical"--perhaps a reference to Mother Africa. There are several other naming theories. There are also many pronunciations thrown about, but the correct way to say it: CONE-gah. A conga drummer is a conguero (cone-GARE-oh).
In the US, conga drums were mistakenly associated with a particular rhythm called "la conga," but the drums used for that dance are actually a different kind of drum, used only for Carnaval. Tumbadoras were built to play a drum pattern called tumbao.
Congas are uniquely Cuban, probably first made by covering empty rum barrels with animal hides, and tuned by heating the hides with a flame. Prior to the 1950s, congueros generally played only one drum.
After the development of tuning systems with lugs and bolts and drum heads made of synthetic materials, playing congas as a set of two, three, or four became easier logistically, and allowed for a melodic component and for improvisation. That opened the door to using the drums in a wide range of different musical styles.
Listen for conga drum masters Ray Barretto and Samuel Torres this week on Saturday Jazz Caliente. Here's Samuel Torres with "Yaoundé."
Jazz Caliente airs Saturdays at 5:00 p.m. The show is hosted by Robin Lloyd and produced by KNKX Public Radio.