Final answer:
The term 'My lord' in the quote refers to King Claudius, and it is Polonius who intends to eavesdrop on Hamlet's conversation.
Step-by-step explanation:
In the quote 'My lord, he's going to his mother's closet. Behind the arras I'll convert myself/To hear the process,' the term 'My lord' refers to King Claudius. This line is spoken by Polonius, a character in William Shakespeare's play, Hamlet. Polonius addresses Claudius as 'My lord' and describes his intention to eavesdrop on Hamlet's conversation with his mother, Queen Gertrude, by hiding behind the tapestry, which is referred to as an 'arras.