Melee weapons are:
Any attack made using one of the above weapons is considered a "melee attack."
A collective slang term generally used to describe a character who primarily uses a melee weapon. Unlike caster, melee character is generally used to refer collectively to both pure and hybrid melee professions.
Pure Melee Professions
The only pure melee profession in Guild Wars is the Warrior. Basic Warrior armor provides no bonus to energy or energy regeneration, but it provides a maximum of 80 AL, and warriors have numerous adrenal skills. Unlike melee hybrids, Warriors have three weapon mastery attributes, and can use one-handed weapons and shields. The term tank is used far more often than pure melee to refer to the single pure melee class, because Warriors have high AL and numerous defensive skills, although there are some non-melee Warrior builds.
Melee Hybrid Professions
These are professions that use melee weapons, but aren't as heavily focused on them. The two melee hybrids are Assassins and Dervishes, both of which are melee / caster hybrids. Both professions have +2 energy regeneration, +5 energy and a maximum AL of 70 on their basic armor. Because they have a lower AL than Warriors and can't use shields (at least with their primary profession's attributes), they are often considered squishy. Both caster / melee hybrid professions have a single weapon mastery attribute tied to a two-handed weapon, but, unlike warriors, they have no adrenal skills. They are also capable of casting spells, but unlike pure casters they have no wands, staves or foci tied to their attributes.