1 : curving like an eagle’s beak
2 : of, relating to, or resembling an eagle
an aquiline nose
This is another one that’s purpose on the list to give a different way to describe something, or because they expect the GM or player to run across it on reading. It’s useful for character descriptions, or perhaps item descriptions. It’s here so the GM doesn’t have to look it up when they read something aloud to the players.