The Old Man
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The nickname amongst the Galactica's crew for Commander Adama (Mini-Series, 33, Bastille Day).
Additionally, "Old Man" is a traditional naval term used as slang for the commanding officer of a ship. It should be noted that the term is used gender-neutrally regardless of whomever is commanding; thus, Admiral Cain was also "the old man" of the Pegasus and may have been addressed as that at one point or another.