I'm fairly new to the game. I picked up enchanting, and have progressed pretty well so far (265+). To my knowledge, you can only have one enchantment on an item at a time.
However, I frequently see requests in the Trade channel looking for "WTB +Agility +Strength combine", or something similar. I've also noticed some high level characters with an enchanted item that appears to have two enchantments (for example, the leggings on this character: http://armory.worldofwarcraft.com/character-sheet.xml?r=Korgath&n=Korgoth ).
So my question is, what exactly does "combine" mean? Is there actually a way to combine two enchantments into one?