Originally called "Thunder" in Japanese, Nintendo decided to give the various Pokémon species "clever and descriptive names" related to their appearance or features when translating the game for western audiences as a means to make the characters more relatable to American children. Zapdos' English name comes from a combination of Zap, relating to electricity, and dos, the Spanish word for two.

Zapdos, known as the Electric Pokémon, is a legendary Pokémon, one of the legendary birds, along with Articuno and Moltres. It may be based on the thunderbird. Zapdos has the form of a large bird with black and yellow plumage, with its spiky feathers make it look as if it were made of lightning. Its tail feathers stick out in several directions, furthering this illusion. A large crest of feathers decorates its head, and distinctive black rings encircle its eyes.

Zapdos is always seen in conjunction with thunderstorms, because it gathers energy from the electricity in the atmosphere, and is said to live in such clouds. It also causes massive crackling and snapping sounds when it flies; these are contributed to the lightning bolts it is said to shed when airborne.