Magnolia is based on an original screenplay written by American filmmaker Paul Thomas Anderson, who also directed the movie.

Just as there are many thematic layers to the film itself there are several layers to the title:

• Magnolia Blvd. is a street in the San Fernando Valley where the film takes place.

• Magnolia sounds similar to "Magonia", a term created by Charles Fort (who wrote about strange phenomena and is referenced in the film's closing credits) which is an alleged place in the sky where things are kept until they fall from it.

• There is a legend that the bark of the Magnolia tree can cure cancer.

• A magnolia is a type of flower, which is used as a symbol throughout the film. The concept of the blooming flower has been used as an analogy for the film's structure and flow.

• Magnolia is an 8-letter word with 2 "a"s being the 2nd and 8th letters. This is an odd coincidence which relates back to the numbers 82 featured frequently in the film as a reference to Exodus 8:2: "If you do not let them go, I will send a plague of frogs."

• On the morning of 28 June 1957, small fish, frogs, and crayfish fell by the thousands during a rainstorm at Magnolia Terminal near Thomasville, AL. Many of the fish were alive and placed in ponds and swimming pools. There was an F2 tornado 15 miles to the south near Whatley.

The film is constantly addressing the juxtaposition of peoples' lives. Throughout this film, characters are interacting due to happenstance either directly or indirectly. The characters are not all absolutely connected all the time, but they are in ways relative to each other like the petals of a flower. The reason a magnolia flower was specifically chosen to portray this theme is for all the reasons above.

Claudia is connected to Jim Kurring because of their first encounter and that he is protecting her. Jim Kurring is connected to Jimmy Gator because both men have the first name "Jim" and are related to Claudia in different ways since Jimmy Gator is Claudia's father and Jim Kurring is called over to Claudia's house specifically because of an incident involving Claudia yelling at her father to leave her house.

Jimmy Gator is connected to Donnie Smith because both have a drinking problem and Donnie was on the "What Do Kids Know?" game show as a child. Donnie is connected to Phil Parma because both smoke Camel cigarettes and both are connected to Earl Partridge who is the owner of the game show "What Do Kids Know?" and is being taken care of in bed by his nurse Phil Parma.

Linda Partridge is connected to Earl because they are married and are both connected to Frank T.J. Mackey because he's Earl's son and Linda doesn't want him involved in the will. Frank is connected to Stanley because they are both embarrassed on TV simultaneously for different reasons and both have issues with their fathers. Stanley is therefore connected back to Claudia because she too has an issue with her father who is Jimmy Gator the host of "What Do Kids Know?" which Stanley is on.

All the characters are essentially connected to the show.

When Officer Jim decides to casually talk with Claudia, he mentions that if she's afraid to speak out, he would be on a "one eight seven". 187 is the LAPD scanner code for Homicide.