The Side braze is a rectangular ceramic package that has leads extending from both of its longer sides, thus forming two sets of in-line pins.
Unlike the CDIP which has separate upper and lower ceramic bodies, the side braze package has a single ceramic body. This single body has a cavity on top where the chip is placed and bonded. The side braze package is hermetically sealed with a metal cap.
"Brazing" is a type of soldering. The reference is to the manner in which the package is sealed. Just to add, that there are 'hard' and 'soft' solders. Soft soldering is when it melts ~300 degrees Celsius and hard is usually over 800deg C. So the brass solder is used in that case. The ceramic package is usually white Aluminium oxide. The silicon die should survive most kinds of improbable disasters in outside environment.