Sibelius 

1) The most prominent (And just about only) Finnish composer. Lived from the late nineteenth century well into the middle of the twentieth. Famous for his seven symphonies, particularly the second and the fifth. Also produced such well known classical pieces as 'Finlandia', Finland's unofficial anthem, Valse Triste', his Violin Concerto, and his choral symphony 'Kullervo'. Although he lived up to 1952, he did not compose any new pieces after approximately 1920.

2) A music notation program known among the musical community for being annoyingly overpriced and very useful at the same time.

Sibelius is the only composer I know who can write music that reduces an entire audience to tears with his music (well, rappers can, but in a different way)

Sibelius by Lemminkainen September 6, 2010

Sibelius 

a computer program that music teachers use to cheat

Student #1: Can you make me a CD of my vocal part?
Teacher: Sure, I just have to download Sibelius.

Sibelius by Patrick0124578 March 9, 2009

sebelius 

to negligently ignore critical items in an oblivious manner with devastating consequences to large groups of people with the ulterior motive to fecklessly blame one's opponents for the subsequent widespread panic, chaos and wreckage.

Distantly related to the terms SNAFU, FUBAR and BOHICA due to their governmental origins although more to do with the civilian federal bureaucracy than the military.

Citizen 1: I have tried 30 times to get onto helathcare.org so I can get insurance for my family.

Citizen 2: I thought obama fixed that

Citizen 1: no but he sure sebeliused the crap out of the tea party on this one.

sebelius by Matoh Wakan October 28, 2013

Siberius 

Greatest bloody name in history

Guy: Siberius Miyazawa is a bloody lad

Siberius by ben the lad November 16, 2016