In Matt: 16:18
And I say to thee: That thou art Peter; and upon this rock I will build my church, and the gates of hell shall not prevail against it. (Douay-Rheims)
The underlying Greek uses the term hades---which, I surmise, does not mean the same thing as gehenna, which of course, is used elsewhere in the New Testament.
"Hades," like its Old Testament counterpart, sheol, from what I gather, seems to have a double meaning prior to Christ's crucifixion: (i) a place where souls went to after leaving this world (ii) the "limbo of the Fathers" where righteous souls went to await their release by Christ.
"Gehenna" always means: the place where the damned suffer eternal punishment.
So, it seems that the generic term, "hell" has might have three different meanings.
QUESTION: Do we know for sure which "hell" is meant by Our Lord in Matt. 16:18; or, might it have multiple meanings as St. Thomas Aquinas might tell us when trying to interpret Scripture? I am seeking an answer from a Catholic perspective. Thank you.