For the film's Polish release, the title was changed to The Electronic Murderer because the word "terminator" phonetically translates to "apprentice" there. That would be a way different movie. (Source)

Michael Biehn collaborated with James Cameron in three of the best science-fiction films of the 1980s: The Terminator (1984), Aliens (1986), and The Abyss (1989). Either as a running gag or by coincidence, Biehn's characters have their hands bitten in all three films. Sarah Connor bites him in The Terminator, Newt noshes his digits in Aliens, and Ed Harris chews the Biehnery in The Abyss. (Source)

Science-fiction writer Harlan Ellison took Orion Pictures to court, claiming The Terminator was a rip-off of his Outer Limits episode "Solider," which was an adaptation of his short story "Soldier From Tomorrow." While Ellison and Orion settled out of court, the film remains affected by these legalities, as the producers were required to provide a special "thank you" to Ellison in the film's credits. (Source)

Arnold Schwarzenegger has only 17 lines of dialogue in the film. His famous catchphrase—"I'll be back"—is line 15. You have to give him credit: it's impressive that he managed to build a career out of only 65 words. Heck, at this point, it's taken us almost as many words to explain how few words he spoke in the film. (Source)

Orion president Mike Medavoy originally wanted O. J. Simpson to play the Terminator because he was impressed by the football-player-turned-actor's athleticism in a Hertz commercial. Director James Cameron didn't like the idea, because, in his own words, he thought an "African-American man chasing around a white girl with a knife" would prove problematic. Yeah… (Source)