Follow your heart, acushla! 'Tis a safer guide than any promise before you knew what it was that you were saying.
—Arthur Conan Doyle, The Valley of Fear, 1915
Acushla comes from the Irish Gaelic cuisle, which can mean "darling" but more literally means "pulse" or "vein." It's an adaptation of the Irish Gaelic a cuisle ("oh darling"). Cuisle was sometimes also paired with ma to give us macushla ("my darling"), as well as our next term of endearment....