What does "southern" mean?

Southern: Of or pertaining to the south; situated in, or proceeding from, the south; situated or proceeding toward the south. Southern Cross (Astron.), a constellation of the southern hemisphere containing several bright stars so related in position as to resemble a cross. -- Southern Fish (Astron.), a constelation of the southern hemisphere (Piscis Australis) containing the bright star Fomalhaut. -- Southern States (U.S. Hist. & Geog.), the States of the American Union lying south of Pennsylvania and the Ohio River, with Arkansas, Louisiana, and Texas. Before the Civil War, Missouri also, being a slave State, was classed as one of the Southern States.