Kali/Arnis/Escrima-are all martial arts of Filipino origin. Some people believe that the terms are tied to the regions the art originated in, there is little proof to support this claim.
In addition many people think that Kali is primarily used when describing bladed arts and arnis/escrima apply to stick arts. Again little proof exists to substantiate this claim.
In my opinion the terms are interchangable and are more closely linked to the time the art was popularized here in America.