Abjuration
This school is focused on protective spells, as well as spells which cancel or interfere with other spells, magical effects or supernatural abilities, such as Dispel Magic or Remove Curse.
Alteration/Transmutation or Transmutation
Spells in this school alter the properties of their targets. Examples include Fabricate, Polymorph, Plant Growth, Move Earth, and Water Breathing.
Conjuration or Conjuration/Summoning
Spells in this school are focused on instantaneous transportation, conjuring manifestations of creatures, energy or objects, and object creation.
Divination
Spells in this school are focused on acquiring information, and include spells such as Detect Magic, Identify and Read Magic.
Enchantment or Enchantment/Charm
Spells in this school, such as Charm Person or Symbol of Persuasion, affect the targets' attitudes, usually making them act more favorably toward the caster, or spells such as Confusion, Feeblemind, Sleep, or Suggestion can force the targets to act in a certain way or avoid certain actions, affect the targets' emotions or affect the targets' minds in other ways.
Evocation or Invocation/Evocation
Spells in this school are focused on damaging energy-based spells such as Fireball, Lightning Bolt, Cone of Cold, Wall of Force, Darkness, Light, Leomund's Tiny Hut, and the Bigby's Hand spells.
Illusion or Illusion/Phantasm
Spells in this school create artificial sensations with no physical substance, or can alter the target's sensory properties, and can cause invisibility, can create insubstantial images which affect the minds of the viewers, and can create hallucinations which can be harmful.
Necromancy
Spells in this school involve death, undeath, and the manipulation of life energy. Necromancy can usually be divided into three or four categories: spells that help or create the Undead; spells that hurt the Undead; spells that hurt other people; and spells that manipulate life in order to heal.