$\rightarrow$ Primary Growth : With the help of lateral meristematic tissue, length of root and stem grows. It is called primary growth.
$\rightarrow$ Secondary Growth : After completion of primary growth, mainly dicot plants thicken. This increase in thick thickening is called secondary growth.
$\rightarrow$ Types of secondary growth : Two types of lateral meristem take part in secondary growth. Vascular cambium and cork cambium.