What's the difference between BR30 and PAR30 bulbs?

BR30 (bulged reflector, 30/8 inch = 3.75" diameter) throws a wide flood beam and is the standard fit for most 5" and 6" residential recessed cans. PAR30 (parabolic aluminized reflector) is a tighter, more controlled beam typically used for accent or spot lighting, and many PAR30/PAR38 bulbs are wet- or damp-rated for outdoor soffits and porches.