Weapons
Classes. Melee: swords, axes, clubs and fists. Ranged: bows and crossbows. Casters: wands and rods. Wands come in two kinds: caster wands and attack wands (see below). Plus shields and spellbooks in the off-hand.
Swords, axes and clubs come in one-handed and two-handed forms at every tier. Two-handers hit harder but cannot take a shield.
Bows need no ammunition. A bow and a crossbow each hit by their own damage and speed, as often as you like.
Local stats. A weapon's damage, critical chance and attack speed are rolled on the weapon itself. Affixes such as "increased physical damage" in the weapon's own tooltip change the weapon, while those on other items add to your character (Affixes).
Attack speed. Every weapon has its own rate, which you can raise with affixes, runes and the tree.
Spellbooks, wands and rods. The twelve classic wands and the rods are caster weapons: their implicit is spell damage (rods also maximum mana), and they roll spell affixes: spell damage, elemental damage, maximum mana %, spell cooldown, spell mana cost, spell effect, spell area, spell critical chance and spell rank. A spellbook gives spell damage instead of block and rolls the same spell affixes. Casters therefore choose between a wand and a shield, or a rod and a spellbook.
Attack wands. Six wands are made for auto-attacks, not spells. They hit with a fixed element and have an attack damage implicit: Ember Switch (tier 1, fire), Rime Baton (tier 3, cold), Storm Lash (tier 5, lightning), Thornbark Striker (tier 7, earth), Cinder Scourge (tier 9, fire) and Winterfang Baton (tier 11, cold). Their tooltip reads "Attack Wand". They roll attack affixes (damage added to attacks, elemental damage, leech, attack speed, critical, on-hit, accuracy) and never the caster-only spell affixes, except spell rank, which rolls only for projectile, physical, area, chain and wave spells, never melee. Tier 12 has no attack wand.
Spells vs weapons. Weapons make your auto-attacks stronger. Your spells use their own damage, scaled by rank, glyphs and the tree (Spell ranks). Some keystones tie the two together (Keystones).
Elemental damage. Fire, cold, lightning and earth are the four elements. Holy and death are separate damage types with their own resistances (Damage types and resistances).
Weapon-specific runes. A rune socketed in a weapon gives an offensive bonus, while the same rune in armour gives a defensive one (Runes).
Level requirement. Your character level must be at least the base's level (Bases and tiers).