The term "droid" is a contraction of "android," which is a Greek word meaning "humanlike," and is used today in the sense of "man-made being with intelligence." In that sense, it is similar to the word "robot," except that "robot" is restricted to mechanical beings, whereas "android" covers both mechanical and organic beings (the latter usually called "cyborg").

Whenever there is a need for term to cover a highly specialized meaning, languages have found it very useful to "outsource" the requisite term, mostly from dead languages. Greek and Latin have been especially helpful. A good example is the word "Cyberspace."

Such words are used across modern languages without the need to translate them to English, Arabic, or any other modern language. The whole idea is to retain their fossilized form to indicate their specialized (usually high tech) meaning.

To read more about droids, look them up in an encyclopedia, such as in http://www.wikipedia.com