Final answer:
The greeting or opening of a block style business letter is called the Salutation, which is left-justified and followed by a colon.
Step-by-step explanation:
The greeting or opening of a block style business letter is called the Salutation. It typically starts with the word 'Dear' followed by the recipient's title and last name, such as 'Dear Mr. Smith' or 'Dear Dr. Johnson'. If the writer does not know the recipient's name or title, a general salutation such as 'To Whom It May Concern' is used. In block formatting, which is the most common way to format a business letter, all elements including the salutation are left-justified. It is important to follow with a colon (:) after the salutation and leave a blank line before starting the body of the letter.