Final answer:
The cambium refers to the lateral meristem, which is responsible for the secondary growth of a plant, increasing its girth.
Step-by-step explanation:
The type of meristematic tissue that is also known as cambium is the lateral meristem. Specifically, the term 'cambium' often refers to the vascular cambium, which is one type of lateral meristem. There are two types of secondary meristems, both of which are called cambium: vascular cambium and cork cambium. The vascular cambium is responsible for adding layers of vascular tissue called secondary xylem (wood) and secondary phloem, thus contributing to the increase in girth of the plant stem or root. This process is known as secondary growth. In contrast, apical meristem is involved in primary growth by extending the length of the plant at the shoots and roots, while intercalary meristems are found at nodes and bases of leaf blades mostly in monocots.