Imulieribus is a Latin word meaning "among women." While not strictly Italian, it's a key part of this famous Latin prayer, making it unique and historically significant within the context of the song.
In "Ave Maria," it's part of the phrase "Benedicta tu in mulieribus" (Blessed art thou among women), referring to Mary's unique blessedness. It's a beautiful and ancient word that connects the song to centuries of tradition.