parenthetical, actor direction
[character direction or instructions for the actor in the screenplay that] indicates how dialogue should be delivered, inserted, single spaced, situated midway between Character Cue and Dialogue. (Costello, 2004) Only to be used where a line of dialogue might be interpreted in some way contrary to logic. (Griffiths, 2015) Also known as a "wryly" because of the propensity of amateur screenwriters to try to accent a character's speech -- as in BOB (wryly) -- an inflection to a speech noted by a writer. Of course, in stageplays, all stage directions (at least in Manuscript Format) are in parentheses, but "directing off the page," as it's often called, is equally frowned upon. (Screenwriting.info, 2017)