Sentence:  On the first floor, over the gate passage and tower rooms, was a massive hall, well-appointed despite its having to accommodate the inner portcullis and <WSD>murder hole</WSD>, the slots for which may still be seen in the floor. 
Meaning of the word marked with <WSD> tags:  (rare) A chamber above the entrance to a fortification where defenders hide and  shoot at invaders trapped in the entryway below.