Overheard in New York

Professor: What words do we get from the name Aphrodite?
Student #1: Hermaphrodite.
Professor: Yes — from the union of Aphrodite and Hermes. What else?
Student #2: Aphrodisiac!
Professor: Good! And what is an aphrodisiac?
Students: [Silence.]
Professor: Are you all Victorians? Come on… What’s it called when one uses something to arouse sexual appetite?
Student #3: Necrophiliac! [Class laughs.]
Professor: I have to advise you to invest in a dictionary, as it’s simply prudent to know the difference between a necrophiliac and an aphrodisiac. Hopefully, you won’t ever need to thank me for that.