All cacti are succulents, but not all succulents are cacti.

A succulent is defined as any plant that has naturally adapted its structure to maximize the storage of water. They are characterized by thick tissue that can store water in their stems, leaves, or roots depending on the specific plant species.

While cacti typically store water in their stems, other succulents use their leaves (no leaves for cacti) and roots for water storage as well.

Most succulents do contain leaves, with many of them being oriented in unique and mesmerizing patterns. These leaves are often thick to retain water. Additionally, not all succulents are flowering plants, unlike cacti, and they don’t typically have spikes.

Cacti are family within the broader category of succulents. Cacti are a type of succulent that use their stems and branches for storing water.

The most significant difference that separates a cactus from any other succulent or plant is the presence of areoles. These are spots on a cactus that hair, spines, bristles, and spikes come out of. These may vary in their appearance, including size, color, and shape. Some species may grow new branches from these areas, but they are most similar to the creation of a bud.

Unlike succulents, in cacti species the regular leaves  comprise of spines, which mainly protect them from predators.