Type: Charm
Pronunciation: ecks-PECK-toh pah-TROH-numb
Description: This charm is a defensive spell which will conjure a spirit guardian of their positive emotions to defend against dark creatures; it can also send messages to other witches or wizards. The Patronus takes the form of an animal, unique to each person who casts it. The form of a Patronus can change when one has undergone a period of heightened emotion.
Seen/Mentioned: Taught to Harry by Professor Lupin; Harry later taught Dumbledore's Army this charm. This is the only known spell effective against Dementors or Lethifolds.
Etymology: Patronus means "protector" in Latin; in archaic Latin, it means "father"; considering the form Harry's takes, this is interesting. The Latin word expecto means "I await"