acushla

Pronounced "ah-KOOSH-la". An Irish term of endearment meaning "darling" and generally reserved for one's female SO.

I've read that this translates literally as "my pulse", which seems like a very pleasant thing to call someone.

Somewhat later, ryano was kind enough to confirm my guess, and to inform me further; these are his words:

You'd normally say "a chuisle, a chroí" (pron. "acushla acree"), which means, "My pulse, my heart", or "a chuisle mo chroí", which means "Pulse of my heart".