Adam Clarke on Acts 12:13

As Peter knocked - The door was probably shut for fear of the Jews; and, as most of the houses in the east have an area before the door, it might have been at this outer gate that Peter stood knocking.

A damsel came to hearken, named Rhoda - She came to inquire who was there. Rhoda signifies a rose; and it appears to have been customary with the Jews, as Grotius and others remark, to give the names of flowers and trees to their daughters: thus Susannah signifies a lily, Hadassah, a myrtle, Tamar, a palm tree, etc., etc.