An acronym used to refer to the "Catholic Youth Organization". In its most common form, it is used to describe Catholic sports leagues amongst the children of the catholic religion. Basketball is the most common sport in reference to CYO and teams are comprised of the age range from grades 3-8
There was a great CYO game last night between two really good teams
by CrimsonFury February 04, 2008
A slang term for cello, often used by super orchestra geeks on sites like myspace and facebook.
I love playing cyo! Cyo is the best instrument in orch!
by Minimoonaria May 03, 2008