meridional

1. Of or relating to meridians or a meridian.
2. Located in the south; southern.
3. Of or characteristic of southern areas or people.

[Middle English, pertaining to the sun's position at noon, from Old French meridionel, southern, from Late Latin merīdiōnālis, from Latin merīdiānus, of midday, southern. See meridian.]

Of or relating to meridians or a meridian.

The adjective has 2 meanings:

Meaning #1: of or relating to a meridian
  Pertains to noun: meridian (meaning #2)

Meaning #2: located in the south or characteristic of southern people or places