In English, Missing most obviously refers to the fact that Kaede's father is missing. On a deeper level, "missing" could also refer to what is missing in the relationship between Satoshi and Kaede that leads to the father keeping secrets from his daughter. This is evidenced in the movie especially well in the final sequence. In Japanese, the title is Sagasu. "Sagasu" means "to look for," which holds a similar yet slightly different meaning in the movie. Everyone in the film is searching for something. Physically, Kaede is searching for her father, and Satoshi goes off searching for the killer. Additionally, everyone is searching for something intangible that gives their life meaning.