How did Aragorn, Legolas, and Gimli know what Uruk-hai were?

Question

In Peter Jackson's film adaptation of The Lord of the Rings, we see Saruman as he takes the initial steps towards creating a new army. The orcs under his command proceed surprisingly quickly, and Gandalf later explains to Elrond that "Saruman has crossed orcs with goblin-men. He's breeding an army in the caverns of Isengard."

Later, when Saruman is speaking with Lurtz, he briefly relays the history of the orcs, and proclaims the Uruk-hai to now be the pinnacle of orc-kind:

Do you know how the orcs first came into being? They were elves once... taken by the dark powers... tortured, and mutilated... a ruined, terrible form of life. And now... perfected. My fighting Uruk-hai.

_{^{- Saruman, The Lord of the Rings: Fellowship of the Ring (2001) - The Fighting Uruk-hai}}

This all seems to suggest that the Uruk-hai are a new breed, and would likely be unfamiliar to the main characters. This definitely seems to be the case in books, where they only identify them as some type of orc:

And Aragorn looked on the slain, and he said: 'Here lie many that are not folk of Mordor. Some are from the North, from the Misty Mountains, if I know anything of Orcs and their kinds. And here are others strange to me. Their gear is not after the manner of Orcs at all!'

There were four goblin-soldiers of greater stature, swart, slant-eyed, with thick legs and large hands. They were armed with short broad-bladed swords, not with the curved scimitars usual with Orcs; and they had bows of yew, in length and shape like the bows of Men. Upon their shields they bore a strange device: a small white hand in the centre of a black field; on the front of their iron helms was set an S-rune, wrought of some white metal.

_{^{The Lord of the Rings: The Two Towers - Chapter I: The Departure of Boromir, pp.17-18}}

In fact, to my recollection, the term "Uruk-hai" wasn't even mentioned in dialogue until the Battle of Helm's Deep (specifically, in Chapter VII: Helm's Deep, on p. 145; and please note that I am referring to the dialogue, so the title of Chapter III doesn't count here).

But, in the film adaptation of The Two Towers when the trio meets Éomer, Aragorn refers to the horde they're following as "a party of Uruk-hai" (and earlier, Legolas told the others that "the Uruks turn northeast... they're taking the hobbits to Isengard!").

How did they know what they were called?

Answer 1

I don't have the movie available, but using the book it's possible to come up with some explanations.

Simple and short:

Uruk means ork.

Despite being Black Speech (the language of Mordor) it seems to be a widely used and known term, as evidenced by Gandalf using it during their camping trip to Moria and nobody asking "uruwhat?"

Then we have Hai, which means folks. So Aragorn knows about Uruks, then sees a bunch of Uruks that are not the usual ones, and christens them "Ork folks", like in "different but still orks anyway".

No plot hole here; someone in the comments is pointing at the fact that it doesn't make much sense that Aragorn would call them with a name in Black Speech, but the point is that their name is in such language to begin with, and it would be weird to call them half in a language and half in another.

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Little longer explanation: different media, different needs.

In the books Aragorn still knows the term Uruk. Then, during the battle at Helm Deep, he's standing above a wall having a sort of discussion with an army of orcs who identify themselves (a few times) as Uruk-Hai. Let's note for a moment anyway that Uruk-Hai is the name that they give to themselves, so it's quite a coincidence that Aragorn picked up the exact same name for them, in the movie, no?

Actually the point is that a book has a different story telling and different needs than a movie. The three movies are already three hours long, people need to be able to focus on things and remember who's who. Giving a name to a group of enemies help people to follow the dialogs, to identify the enemies, and the dialogs themselves to be a little more short and on point.

So yeah, it's quite a combination that Aragorn comes up with the same name for this "new breed" of Uruks, but to be honest it doesn't break anything, it doesn't feel like a plot hole. And after all in the movie, as long as I can remember, we don't happen to assist to a moment when Aragorn and the other characters list every bit of knowledge they know. What if Uruk-Hai is a widely know term in the movie lore? Why should we expect Aragorn in the movie to not know something because he doesn't know it in the book?

Actually, on this specific point the movie may even be better then the book..._gasp!

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An aside: LOTR books and the Uruk-Hai inconsistency...

And yeah, if we want to nitpick, the real oddity is in the books, not in the movie.

In the books the first batch of Uruk-Hai is created by Sauron a few hundreds years (in 2475 of the Third Age) before the birth of Aragorn. And I may be wrong, but I have a feeling that thousands of enemies scouring Middle Earth, killing and plundering, waging war here and there, conquering entire cities, hardly would go unnoticed.

Really, there's no way most of Middle Earth population ignores who they are. And Aragorn, born hundreds year later, a hunter and explorer like no one before, who's traveled and seen practically every squared centimetre of the world, does not know about their existance? Impossible, to say the least.

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My solution to the double conundrum

In the books Aragorn has no idea where those Uruk-Hai are from, not who they are. In fact, he simply states:

And here are others strange to me. Their gear is not after the manner of Orcs at all

He doesn't recognise their equipment, not their race.

In the movie, Saruman says

my figthing Uruk-Hai

pointing at the fact that they are his own breed, not that he invented them. And to directly quote the book for a nice fan service, too ("fighting Uruk-Hai" is repeated a few times from the Uruk-Hai at Helm Deep when they identify themselves)

In neither case there is any instance where Tolkien or P.J. have Aragorn saying "Know what, dude? Never heard before the term Uruk-Hai".