The A in "George A. Holt" represents the abbreviation of the middle name (or the middle name itself).
In many cultural backgrounds, in addition to the personal name and surname, there can also be one or several "additional names" added between the surname and the personal name, usually called middle names.
Take English as an example:
Middle name(s) can be a first name - such as Michael in Anthony Michael Hall, or a surname - such as George Walker Walker in Bush; there can be one middle name - such as Woodrow in Thomas Woodrow Wilson, or several - such as Ronald and Reuel in John Ronald Reuel Tolkien, or none.
In the United States, the middle name is usually abbreviated to the first letter or omitted. For example, Mary Jane Lynch will shorten her name to Mary J. Lynch - this is also commonly used when signing, or when signing. In daily life, it is directly abbreviated to Mary Lynch; in the UK, the personal name and middle name are often abbreviated to the initials, or the middle name is omitted. For example, Mary Jane Lynch will be written as M. J. Lynch, Mary Lynch or Mary in most cases. Jane Lynch.
Some people also choose their middle name as a common title. In this case, when abbreviating the name, the middle name is written in full and the personal name is abbreviated to the first letter - as in J. Edgar Hoover (full name John Edgar Hoover), or simply omitted - as in Mitt Romney (full name Willard Mitt Romney) .
There are also a few cases where the middle name itself has only one letter, such as Harry S Truman.
When Chinese translates foreign names, it may be translated in full name or in abbreviated form. For example, Edward John Smith (E. J. Smith) can be translated as full name Edward John Smith, or as Edward John Smith (E. J. Smith). E.J. Smith; Franklin Delano Roosevelt (Franklin D. Roosevelt) can be translated as the full name Franklin Delano Roosevelt, or as the abbreviation Franklin D. Roosevelt. The same goes for the A in George A. Holt; it may also be the case in Harry S Truman's translation of Harry S. Truman, where A itself is a middle name, not the abbreviation of the middle name.