c'est à dire (Fr.). That is to say.

ceteris paribus (L.). Other things being equal.

chacun à son goût (Fr.). Every one to his taste.

chère amie (Fr.). A dear (woman) friend.

chef d'œuvre (Fr.). A masterpiece.

ci devant (Fr.). Formerly; heretofore.

comme il faut (Fr.). As it should be.

compagnon de voyage (Fr.). A travelling companion.

con amore (It.). With love; very earnestly.