buxom caryatids (page 23) -- A sculpted female figure serving as an architectural support taking the place of a column.
estuary Egyptian slang (page 60) -- A semi-enclosed body of water flowing into the sea. On reflection, it is obviously referring to the slang used by the peoples of the Nile estuary, since this scene takes places in Alexandria.
anthropophagi (pg. 258) -- Cannibals.
tumuli (pg.9) -- A mound of earth and stones raised over a grave or graves.
gout (pg. 27) -- A mass or splash, as of blood; spurt. Or in this case, lightning. I think.