A synonymous pair that derives from the same ancient source without a difference in meaning is a bit more uncommon, but that’s exactly (and fairly obviously) what we find with centenary and centennial, words that mean “a 100th anniversary or its celebration.” Both words can be used as adjectives as well as nouns. They ultimately derive from the Latin word centum meaning “hundred,” but they took different paths into English.
Centenary is the older word in English, having derived directly from the Latin word centenarium in the 15th century. The English word has had several meanings, including “a weight of 100 pounds” (a meaning that is now obsolete) and “a period of 100 years” (a synonym of century that is also obsolete in modern English).
Other uses of centenary referred to specific administrative positions. It was used to mean “an officer in command of a group of 100 soldiers,” because century could mean “a group of 100 Roman soldiers.” In this use, centenary was a synonym of the more familiar centurion. Similarly, centenary was used to mean “the governor of a county hundred,” because hundred was used to mean and “a subdivision of some English and American counties.”
Centennial dates only to the 18th century, and was formed from the Latin word for “one hundred,” centum, with the -ennial suffix derived from the Latin annus meaning “year” and also seen in words such as biennial, millennial, and perennial.
It’s interesting to note that a third variation also exists: centennium has occasionally been used to mean both “a period of 100 years” just as millennium means “a period of 1000 years,” and “a 100th anniversary,” but its use is so rare that it is only included in the historical Oxford English Dictionary.
‘Centenary’ is more popular in British English, while ‘centennial’ is preferred in the United States.
Music
Bonobo: Sleepy Seven
Florence + the Machine: 100 Years
Beastie Boys: Transition
Gorillaz feat. Tony Allen and Skepta: How Far?
Say Yes Dog: Feel Better
SBTRKT: Look At Stars
The Cinematic Orchestra: Ode To The Big Sea
BADBADNOTGOOD feat. Arthur Verocai, Terrace Martin & Brandee Younger: Talk Meaning
Damon Albarn: The Nearer The Fountain, More Pure The Stream Flows
Cigarettes After Sex: Starry Eyes
Sergio Mendez & Brasil ’66: So Many Stars
Herb Alpert & The Tijuana Brass: Never On Sunday
Boards of Canada: Constants Are Changing
A community radio midnight show Through the Bohemian Looking Glass is aired Sunday, Tuesday and Friday night at midnight (GMT), that means you stay late on Saturday, Monday and Thursday. A new episode is aired every Sunday midnight (the night between Saturday and Sunday) on Wirral Wave radio or AirTime. Later on SoundCloud for some time.
Through the Bohemian Looking Glass 