An enchantment is a type of spell. Defined as something to charm or bewitch.
In this context it sounds custom made for witches.
Enchantment is also in the D&D family of RPGs a School of Magic.
According to Wikipedia:
Enchantment or Enchantment/CharmWhen I was first working on my witch class I went through the books and thought about which spells would be good for the witch. Enchantment spells came over whole cloth.
This school, known as Enchantment/Charm prior to 3rd edition and Enchantment in 3rd and 3.5 editions, changed dramatically in 3rd edition, when all non-mind-affecting spells were removed from the school and many were moved to Transmutation. In 3rd and 3.5 editions, all Enchantment spells are mind-affecting and Enchantment is divided into two subschools: compulsion and charm. Charm spells, such as Charm Person or Symbol of Persuasion, affect the targets' attitudes, usually making them act more favorably toward the caster. Compulsion spells such as Confusion, Dominate Monster, Feeblemind, Sleep, Suggestion or Zone of Truth, 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. The Compulsion subschool also includes buffs, such as Aid and Heroism. Wizards who specialize in this school are known as Enchanters.
Later when I updated it for my 3.0 book Liber Mysterium and my Basic Era The Witch I focused solely on spells from the d20 SRD.
I added all the spells to a giant Excel worksheet and then went down the list and compared it to a list I had created over the years of spells I felt were ones good for witches. Where they intersected was my list of spells.
This served me well since these were spells that people knew and they were also ones I felt were good for a witch to use.
I like the idea that witches have a wide choice of spells within the confines of specialties. They might not have the flexibility of a wizard for example, but within their own specialties they have a large number of choices.