Mason “Country” Thomas, 85, a multi-instrumentalist who was a stalwart of the Washington area jazz scene for a half-century and accompanied visiting musicians, including trumpeter Louis Armstrong, died Aug. 24 at Virginia Hospital Center in Arlington after a stroke. He was an Arlington resident.

His death was confirmed by his daughter, Dale Johnson.

Mr. Thomas, who grew up in the Washington area, became entranced by jazz after hearing clarinetist and bandleader Artie Shaw on the radio. Mr. Thomas mostly played reed instruments, including the saxophone and clarinet, but he also was proficient on piano, trumpet, trombone, tuba and upright bass.

He performed at countless nightclubs, hotels and other venues in Washington. One of the groups he fronted was called the World’s Third Greatest Jazz Band; to call it the “second greatest” would be presumptuous, he told friends.

Mr. Thomas specialized in a traditional jazz sound of the 1920s, 1930s and 1940s, with a repertoire that included music initially popularized by entertainers as diverse as Duke Ellington, Fats Waller and Eddie Condon. Among the musicians Mr. Thomas later played with at Washington club dates was cornetist and former Condon sideman William “Wild Bill” Davison.

In a 1979 review, Washington Post jazz critic W. Royal Stokes praised Mr. Thomas in performance. On saxophone, Stokes wrote, Mr. Thomas “displayed his full, big sound with the occasional wispy phrase and a touch of vibrato. Thomas’s vocabulary is full of little riff-like phrases, but there is not a cliche among them.”

Mason Drummond Thomas was born in Washington on Sept. 14, 1925, and raised in Arlington. He spent part of his childhood on a family farm in Fairfax County, leading to the nickname “Country.”

He graduated from the old Augusta Military Academy in Fort Defiance, Va., then served in the Army in Europe during World War II.

As a young musician, he visited New York, where he frequented the 52nd Street jazz scene, visiting with Condon and clarinetists such as Milton Mesirow, known as Mezz Mezzrow, and Charles “Pee Wee” Russell.

“Those guys were really something else in those days ’cause we were just kids and they treated us like we were the greatest thing in the world, buying us food and everything and watching after us to make sure nothing bad happened to us,” Mr. Thomas later told Stokes.

To supplement his later musical career in Washington, Mr. Thomas owned and operated an air-conditioning, refrigeration and heating business until the mid-1990s. In the late 1950s and early 1960s, he left the area and worked in Las Vegas as a musician, restaurateur and bellhop.

His marriages to Lorraine Ward, Nancy Adams and Yus Rustinah ended in divorce.

Survivors include his companion, Nancy Shimer Greathead of Arlington; a daughter from his first marriage, Lynn Hunter of Asheville, N.C.; four children from his second marriage, Jamie France of New Philadelphia, Ohio, Dale Johnson of Manassas, Guy Thomas of Arlington and Kelly Thomas of Warrenton; a stepson, Bo Depretes of Arlington; nine grandchildren; and 14 great-grandchildren.