Ever since the show first aired in 2010, "The Walking Dead" has brought zombies to our TV screens every Sunday night for the past eight years. Not only that, but they seem to have brought back the classic form of zombie that George Romero had popularized and, essentially, created.
This classic approach is something which hadn't been done in quite some time, with zombie movies such as "Warm Bodies" and "28 Days Later" redefining zombies by giving them the capability to love or making them fast and feral, like a wild animal. In many ways, "The Walking Dead" is a return to form for classic zombies, but, at the same time, the show has redefined what zombies stand for.
When George Romero first debuted "Dawn of the Dead" in 1978, he used zombies as a metaphor for a topic he was passionate about- consumerism. Consumerism is a topic that was gaining momentum leading into the 80s, with malls beginning to sprout up and teenagers creating their own "mall rat" culture.
Romero was very outspoken about his disdain for consumerist culture, and his use of zombies as a narrative for this idea is very clear in the film. Between the setting of the movie is in a mall itself, and the characters assuming the zombies are at the mall because it was an "important place in their lives". Romero isn't being particularly subtle about his use of the monsters.
All that being said, while "The Walking Dead" takes the physical attributes of Romero's classic zombies, such as their lethargy, lack of any intelligence, and decaying appearance, the show doesn't really use the attached metaphor of consumerism.
Instead, "The Walking Dead" seems to steer clear of any set metaphor or association for their zombies, allowing their audience to attach meaning or symbolism as they see fit, and giving themselves the liberty to do the same. This is a good strategy for the show, for certain, as it allows them to do virtually whatever they want with zombies, and allows them to pull away from Romero's original associations. The show also does this in the way that it calls the zombies "Walkers" instead of the "living dead" or "undead."
If anyone were to guess what the defined meaning of zombies, or, Walkers, in "The Walking Dead" is, there would be a ton of differing options. On a surface level, the zombies seem to represent the idea of death itself, and little more, but I'm sure that differing arguments of the zombies-as-metaphor could be made if only someone dug a little deeper into the show.