Not contenting himself with false imprisonment, now we see Dracula committing theft.
Portmanteau is an interesting word. "Port" is, I think, a relatively archaic word meaning "bag" that probably evolved from the even more archaic portmanteau. In some sub-dialects of Australian English, "port rack" is (or was, over 20 years ago when I was in primary school) a term for a rack where school kids would put their schoolbags, but I don't think the term port was much used even for the schoolbag itself.