Enchant

Enchant is a keyword ability that restricts what an Aura can target and be attached to. Up until Ninth Edition of the Core game, Auras were know as Local Enchantments. Local Ecnhantments carried all the rules in their type, which agonized R&D. Now that the rules are in the actual Rules Box, Auras can be more diverse and it's easier for beginners to recognize that Auras are Enchantments.

From the Comprehensive Rules:

• 502.45. Enchant
  • 502.45a Enchant is a static ability, written “Enchant [permanent or player].” The enchant ability restricts what an Aura spell can target and what an Aura can enchant.
  • 502.45b For more information on Auras, see rule 212.4, “Enchantments.”
  • 502.45c If an Aura has multiple instances of enchant, all of them apply. The Aura’s target must follow the restrictions from all the instances of enchant. The Aura can enchant only permanents or players that match all of its enchant abilities.
  • 502.45d Auras with the “enchant player” ability can target and be attached to players. Such Auras can’t target permanents and can’t be attached to permanents. Rules 212.4d–i apply to an Aura with enchant player in relation to players as they normally would for permanents.