BOM may refer to any of the following:
1. Short for byte order mark, BOM is another name for the Unicode character at the beginning of a file that indicates whether or not a file is UTF-16 or UTF-32.
2. Short for bill of materials, BOM is a complete listing of everything that makes up a product. For example, a computer purchased from a computer manufacturer has a BOM of every part or a purchasable parts. A BOM contains the name of the part, it's part number, and the quantity of parts.