Spirit: Weapon Rune Word - Diablo 2
Spirit is a Rune Word that is available to both swords and shields but is almost always placed into a shield because there are much better options available for weapons. Only a caster build/class would use Spirit in a weapon and even then only builds that desperately need Faster Cast Rate and can't find a Flail or afford Heart of the Oak Rune Word are the ones that typically use it.
Keep in mind that all Rune Words you create will retain any pre-existing bonuses found on the item. If you find a 'Superior' piece of armor with +Enhanced Defense, a Superior Weapon with +Enhanced Damage or a Helm/Weapon that has +Skill bonuses for a certain class, all of these will remain on the final Rune Word that is created. It's also possible to 'ebug' a piece of Ethereal Armor that you find which will increase the Defense bonuses by 50%, check out my Ebugging Guide for more information.
Farming High Runes: Out of all locations in the game one stands above the rest for farming specifically High Runes, the Countess during Act 1. The Countess has a guaranteed chance to always drop a High Rune and can even drop more than one. Check out my The Countess Farming Guide for more information.
Required Runes: Tal -- Thul -- Ort -- Amn
Level Req: 25
Other Req: Ladder Only
Slots: Shields and Swords Only
Both
+2 To All Skills
+25-35% Faster Cast Rate (varies)
+55% Faster Hit Recovery
+250 Defense Vs. Missile
+22 To Vitality
+89-112 To Mana (varies)
+3-8 Magic Absorb (varies)
Shields
Cold Resist +35%
Lightning Resist +35%
Poison Resist +35%
Attacker Takes Damage of 14
Swords
Adds 1-50 Lightning Damage
Adds 3-14 Cold Damage (3 Sec,Normal)
+75 Poison Damage Over 5 Seconds
7% Life Stolen Per Hit