[feet]

Is security the same thing as reliability?

[riskable]

Not "the same thing" but security is a HUGELY IMPORTANT under the umbrella of "reliability".

If your stuff isn't secure how could you possibly make claims that it's reliable? If I said, "resilient" (synonym for "reliable") instead would it make more sense (in the scope of IT stuff)?

[CRConrad]

But is security even "under the umbrella of 'reliability'"?

Depends (like pretty much everything else) on your definitions, I guess.

I could see defining "security" and "reliability" along orthogonal axes:

"Sure, it's a bit leaky, but it's very, very reliable -- including reliably leaky."

[rantingdemon]

On a high level, security can be thought of as the CIA triangle.

Confidentiality Integrity Availability.