well the words themselves are different..
I dont know what arnis means but kali = weapon and escrima = stick
With all due respect, you are incorrect.
The oldest of the terms is eskrima, a Tagalog word derived from the Spanish word esgrima, which means "fencing".
Arnis is another Tagalog word, also derived from Spanish. The original Spanish term was arnes, which means "harness". It should be stressed that, in this case, "harness" specifically means "armor". The original term was arnes de mano (coined in 1853), which literally means "armor of the hands", and it refers to the Filipino warrior's ability to protect himself with his weapon, as if he had armor. This eventually became arnis de mano, and was ultimately shortened simply to arnis.
"Kali" is a term which is often claimed to be the "original" pre-Hispanic term for Filipino fighting arts, but the truth is that the earliest reference to "kali" comes only from 1957, from Placido Yambao's book on FMA. There has long been a sort of revisionist movement in certain FMA circles, that has attempted to replace the historically correct terminology with "kali". Many FMA styles even changed their names from eskrima and arnis to "kali". The entire "kali" myth is soundly debunked in the new book by Dr. Ned Nepangue and Celestino Macachor, entitled, Cebuano Eskrima--Beyond the Myth.
And the rapier blades, being so narrow and of so small substance, and made of a very hard temper to fight in private frays... do presently break and so become unprofitable. --Sir John Smythe, 1590