A more thorough explanation:

Term: AB

Definition: AB is an abbreviation for able-bodied seaman, which is a rank in the merchant navy. An able-bodied seaman is a person who is physically fit and capable of performing all the duties on board a ship.

Examples:

• John is an AB on the cargo ship.
• The captain assigned the AB to clean the deck.

The examples illustrate the use of AB as an abbreviation for able-bodied seaman. In the first example, John is referred to as an AB, indicating his rank on the ship. In the second example, the AB is given a specific task to perform, which is a common duty for someone in this position.

Definition: AB can also be used as a preposition, meaning "from," "by," or "of."

Examples:

• The package was sent AB post.
• The painting was done AB the famous artist, Picasso.

These examples illustrate the use of AB as a preposition. In the first example, AB is used to indicate that the package was sent from a specific location. In the second example, AB is used to indicate that the painting was done by a specific artist.