IPA: /θiˈætrɪkli/
KK: /θiˈætrɪkli/
In a way that is dramatic or exaggerated, similar to how actors perform on stage.
She spoke theatrically, capturing everyone's attention with her dramatic gestures.
The word 'theatrically' is formed from 'theatr-' (from Greek 'theatron', meaning a place for viewing) and '-ically' (meaning in a manner relating to). Thus, 'theatrically' refers to something done in a manner related to the theater or dramatic performance.
Think of a 'theater' where performances are viewed, and remember that 'theatrically' means doing something in a way that relates to that dramatic setting.