definitions of the block style letter
A: A semi-block style letter is a less formal version of a block or a full-block letter with the differences being the sender's address, date, reference or attention line and complimentary closing. In addition, the signature lines are located direct center or slightly right of center, along with indented paragraphs.
A full block style format for a letter means all the text is left justified. This varies from a semi-modified block style format in which some elements are right justified. Full block format is a... A full block style format for a letter means all the text is left justified.