The description of the general appearance of a lamp/bulb consists of a letter(s) followed by a number. The letter indicates the shape of the bulb and the number relates to the diameter of the bulb in eighths of an inch. For example, a common household bulb is the A-19. The bulb is "A" shape and the diameter would be nineteen 8ths of an inch, or 2 3/8".
The color of the light produced by a bulb
The technology implemented by the bulb, e.g. incandescent, halogen, LED
Also referred to as "Maximum Overall Length" (MOL). For light bulbs, it measures the length of a light bulb, from the top of the bulb to the bottom of the base or pins and is typically expressed in inches. For light fixtures and ballasts, it applies to the total horizontal length of the item.
Light bulbs: a measurement of a bulb's width taken at the widest point of the bulb. Fixtures: the measurement across the widest point of a circular fixture.
A General Electric brand-specific product number for an equivalent item and is provided for the purpose of cross-referencing.