BLOC
The last part of a letter is the signature.
Technically, "epistle" means a letter. The ending of a letter is usually called a "closure," which is simply a polite and accepted form of ending a letter. For example: "Sincerely yours, XYZ"
viper
valediction
titled
suffix
dye-yielding plant ending in il is called anil
covey
There is a city in Utah called Tropic.
alliance
covey (quail)
the signature of a letter is called the complimentary close or ending