"buried the axe in her brain...."See in text(The Black Cat)
Poe’s verb choice—to “bury” the axe—is interesting on several accounts. The verb carries a connotation of the burial of a body, an imminent event in the story’s plot. The combination of “buried” and “brain” in the same phrase—with those repeated b and r sounds—has an appealing poetry to it. Finally, the phrase brings to mind the idiom of “burying the hatchet,” a 17th-century American saying that indicates a truce, or peace-making. Poe may have intended this final meaning in an ironic sense.
"hogsheads of Gin, or of Rum,..."See in text(The Black Cat)
"Hogshead" is a 14th-century term for a large cask or barrel. The detail of the barrel reinforces the thematic connection between the cat and the narrator’s intemperance. The two cats in the story embody the narrator’s violent shadow self. It can be said that the alcohol unleashes that shadow self. Thus, when the cat returns it appears on a barrel of alcohol.
"in a den of more than infamy,..."See in text(The Black Cat)
Poe is clearly referring to a bar, pub or tavern, but the phrasing is rather odd. Perhaps “more than infamy” refers to intemperance, or a habit of excessive drinking.