Castiel meant freedom. Castiel meant doing what was right, not what Heaven commanded. Castiel meant following the heart that was too big for his vessel and opening himself up to love. Castiel meant hope.

Castiel doesn't mean crouching in a dirty parking lot with blood on his hands. Angel blood. Castiel doesn't mean trying to atone and making it all so much worse. Castiel doesn't mean lying and crying and taking them all for fools.

Castiel once held the connotations of power crazed and abomination, but the meaning stayed pure – it always meant help and care and trying to do the right thing, the best thing, he tried. Before that, before the Winchesters were even on the angels' radar, Castiel meant good.

Perhaps Castiel will peter out of existence, slowly trickling down past the 'hither's and 'thine's until it means nothing but old, and only a few remember the proper spelling.

But right now, nobody knows what Castiel means at all.