The brightest pair of binary stars in the night sky; one is a blue-white main sequence dwarf and it's companion is a faint white dwarf. Sirius is located in the constellation Canis Major and as a most visable star is often called the "Dog Star"

The name Sirius comes from Greek and means "Scorcher"; and in Greek mythology Sirius is Orion's hunting dog. And before that, in Egypt the stars Sirius where worshiped as "Sothis".

I couldn’t care less (but one must keep up appearances, right?)

Harry Potters godfather

Satellite radio service where high profile radio personalities (Howard Stern, Cousin Brucie, etc) go when they get pissed at regular radio.

soon to be the new home of Howard Stern

A sirius attitude is an attitude in which the person being sirius should not be taken seriously unless it is a serious matter. If it is not a serious matter, it then becomes a sirius matter, in which case one can simply overlook it to save themselves time.

Sirius can be spelled as SIRUS as well.

A large boxy satalite radio that is often boxed with a trailer. This is so that you can tow it behind the Mack truck you will need to buy to listen.