1. Conforming to the rules of grammar or usage accepted by native speakers
   - grammatical

Encyclopedia: Well-formed

• Catharanthus
• Catharanthus roseus
• Cathari
• Catharism
• Cathars
• catharsis
• Cathartes
• Cathartes aura
• cathartic
• cathartid
• Cathartidae
• Cathay
• Cathaya
• cathect
• cathectic
• cathedra
• cathedral
• cathemeral
• Cather
• Catherine
• Catherine de Médicis
• Catherine Howard
• Catherine I
• Catherine II
• Catherine of Aragon