[quote="Eldorion":wwr4vnz5]Hi Zeonista, welcome to the forum![/quote:wwr4vnz5]
Good to be here, it's fun to talk with other Tolkien fans.
[quote:wwr4vnz5]I'm afraid there is not a single difference between goblins and orcs, not even as a sub-type.[/quote:wwr4vnz5]
Untrue, Tolkien uses the two words interchangeably in LOTR, so they are meant to be divergent Westron words for the same race. See the initial description of the White Hand uruks in TTT, also Gamling's reference to them at Helm's Deep later on. Sam calls Frodo a "proprer orc" after kitting him out in a disguise at Cirith Ungol, even though Frodo would technically be a Goblin in size.
[quote:wwr4vnz5]Goblin is just an English word[/quote:wwr4vnz5]
Goblin is derived from the French [i:wwr4vnz5]gobelin[/i:wwr4vnz5], which refers to a French village and its faerie denizen from folklore. The term crossed the channel with the Normans, I guess.

Christopher Tolkien references it in one of his books, I don't hjave the source at hand right now.
[quote:wwr4vnz5]and Orc and Old English (standing in for Rohirric) word.[/quote:wwr4vnz5]
In Middle-Earth, "orc" is a Westron corruption of the Elvish [i:wwr4vnz5]yrch[/i:wwr4vnz5], the name applied by the Elves to those creatures. Legolas says it twice. Tolkien is having fun with language again.
[quote:wwr4vnz5]I'm not certain that Uruks are all sun-tolerant either.[/quote:wwr4vnz5]
The uruk-hai are explicitly stated to be able to tolerate the Sun, however much they hate it. Sauron, followed by Saruman, designed the sub-race explicitly to be able to fight Men at less of a disadvantage than the original Orcs.
[quote:wwr4vnz5]Certainly Saruman's "Uruk-hai" were, but it's debatable that they were in fact half-orcs and thus not reflective of normal uruks.[/quote:wwr4vnz5]
Sauron originally developed the uruk-hai, and they made their big debut in TA 2475 when troops of them overran Ithilien, temporarily forcing Gondor to cede control of that province. (See ROTK Appendix for history of Gondor.) The uruks were intended to be bigger, stronger, and more capable of discipline, making them better warriors than standard orcs. The uruks knew their own capabilities and lorded it over the lesser original breeds, becoming their leaders and taskmasters. The uruk-hai, and any mixed-blood offspring of theirs derived from common orcs, were readibly discernable from lesser orcs. Gandalf identifies them at Moria, even before the introduction of Saruman's uruk-hai in the story.
Concerning Saruman, when he turned to evil he sought to copy Sauron in many things, in order to be both servant and rival. Since Saruman knew that regular orcs and the diminuative snaga-hai were useless against the Rohirrim in open battle, from the previous battle records of the two peoples. (See ROTK appendices for history of Rohan.) So he decided to make up uruk-hai on his own, with or without consultation from Mordor. How he got the idea, or the means to do it, is unknown, and likely to remain unknown in Middle-Earth, possibly due to a high squick factor. The orc+man breeding program was ultimately successful in giving him uruk-hai of a useful sort. There may have been some differences in appearance between Isengard and Mordor uruk-hai, since Aragorn professes to know the difference at Parth Galen, and be curious about it. (His curiosity may have been less concerned with physical characteristics and more due to the equipment and heraldry, which is described as being unusual.)