capitalization: family relationships

Capitalize terms for family relationships only when the name of a person follows, when they are unmodified, or when they are used in direct address:

• You inherited your keen eyes from Grandfather Smith.
• Did you invite Aunt Sarah?
• We met Mom at the theatre.
• Write to me, Son, and tell me how you are.

but

• John’s grandfather served in the army.
• Our aunt, Sarah Vick, is an engineer.
• Your mother called while you were out.
• Janet and Gordon’s son is visiting them.