Azul is Spanish and Portuguese for blue, possibly a reference to Azula's Firebending.
Her name may also come from the Sanskrit term Asura, a Hindu term for demon.
Azula's name was originally going to be "Zula".

In some Avatar comics, her name is mispelled "Takara" instead of "Katara".
Katara's voice actor, Mae Whitman, has previously played the part as Rose in American Dragon: Jake Long.

The Southern Air Temple is the only episode in which the title screen, which denotes the chapter and book, does not have a white background (the background is the sunrise).
According to the Nick.com's website...