chain letter — A chain letter is a letter, often with a promise of money, that is sent to several people who send copies on to several more people. Chain letters are illegal in some countries.
had better — that which has greater excellence or is preferable or wiser: the better of two choices.
form letter — a standardized letter that can be sent to any number of persons, occasionally personalized by inserting the name of each recipient in the salutation.
dead letter — If you say that a law or agreement is a dead letter, you mean that it still exists but people ignore it.
crank letter — a hostile or fanatical letter, often sent anonymously.
open letter — a letter, often of protest or criticism, addressed to a specific person, but intended to be brought to public attention.
market letter — a publication containing information concerning market conditions, expectations, etc., especially one produced by a securities brokerage firm or other financial organization.
irish setter — one of an Irish breed of setters having a golden-chestnut or mahogany-red coat.
gordon setter — one of a Scottish breed of medium-sized setters having a black-and-tan coat.