dialogue [or voice] spoken by a character who is physically present in the scene, but is not currently on camera [i.e. is not visible]. (Dancyger & Rush, 2013, p. 328) In the screenplay abbreviated as O.S. and written in parentheses next to a character's name in capital letters. (FILMTERM) O.S. is a useful designation if you want to keep the beat focused on the character reacting (the one described by the stage directions) rather than on the character speaking (the one whose dialogue is off-screen). (Dancyger & Rush, 2013, p. 328)