Everything happens for a reason.

No. An oxymoron is a figure of speech that combines two normally contradictory terms. reality is defined as; 1. the state or quality of being real. 2. resemblance to what is real. 3. a real thing or fact. 4. real things, facts, or events taken as a whole; state of affairs: the reality of the business world; vacationing to escape reality. 5. Philosophy. a. something that exists independently of ideas concerning it. b. something that exists independently of all other things and from which all other things derive. 6. something that is real. 7. something that constitutes a real or actual thing, as distinguished from something that is merely apparent. while the word arbitrary means; 1. subject to individual will or judgment without restriction; contingent solely upon one's discretion: an arbitrary decision. 2. decided by a judge or arbiter rather than by a law or statute. 3. having unlimited power; uncontrolled or unrestricted by law; despotic; tyrannical: an arbitrary government. 4. capricious; unreasonable; unsupported: an arbitrary demand for payment. 5. Mathematics. undetermined; not assigned a specific value: an arbitrary constant. A better example of an oxymoron would be VIRTUAL reality, since the word "virtual" is contradictory to the word "reality".

NO. The words Arbitrary and Reality do not have the same or similar meanings.