Xenomorph
About the "xenomorph" name in Aliens. I'm glad someone wrote an article such as this. When Lt. Gorman coined that name he wasn't even aware of what he was talking about. He didn't know what was waiting for them on the surface. It could have been anything. Xenomorph isn't the official name of the species of alien in the film.
I'm also glad they mentioned the whole "bug hunt" thing because a lot of people misunderstood that line too. Even writers of spinoff media. It didn't mean they faced the type of aliens that where in the film before and that they knew they where going to face an insect like foe. As someone said in the forums:
"I can't quote specific lines off the top of my head, but I always interpreted the movies as implying that humans had not run into intelligent life before, but frequently sent Colonial Marines off on wild goose chases ("bug hunts") when there was suspicion of alien life somewhere (a colony reporting a suspicious disappearance or some such)."
and
"My understanding even back then was:
1. Xenomorph is a generic term for any alien not yet know by humanity
2. Bug Hunt is interchangeable with wild goose chase"
Neither is "The Alien" or "Giger's Alien" the official canonical name but most of us call it our preferred name because it doesn't have a good readily available name other than those mentioned above.
The general gist of all this was they (the colonial marines) where ignorant of what was waiting for them on LV-426 and where just being "smarty pants" about it.
Of course later on we got prequels, sequels, comics and games that muddy the water of whether or not they have faced the titular creatures before.
http://arstechnica.com/the-multiverse/2014/08/the-throwaway-line-in-aliens-that-spawned-decades-of-confusion/