IMHO it's worth giving uber-concise definitions of the CIA Triad definitions:
Confidentiality: Only those who should have access, do.
Integrity: Data is what it should be, and chaged only by those with authority
Availability: Systems and Data should be accessible and useful
It's also an interesting side-note how many "CIA+" standards you will see from various security professionals, including:
CIAP: adds "Privacy" which is, you know, confidentiality
CIAA: Adds "Auditing" which is a useful addition. "Transactions and administrative activities should be logged"
CIAO: See you later.