Living creatures share some characters which are not found in the non-living.
Growth is one of such features or characteristic property which is present in the living. The numerical changes or structural changes leading to enhancement in the object, in terms of an increase in size, number, volume, mass, etc. are termed as Growth. There are two main types of physiological reactions, Anabolism and Catabolism. When the cell (or living being) makes up (builds) complex material from simple substances, it is called Anabolism. On the contrary, when the living being breaks complex forms into simpler forms, it is termed as Catabolism.
Growth occurs when Anabolism > Catabolism. This is a characteristic feature of living. Growth in living takes place from within (called Intrinsic growth). 
However, non-living beings, such as Mountain, River, Desert, etc. also grows. This is not intrinsic. The growth seen in non-living beings is external or extrinsic. Additional material is deposited outside and there is an increase in area, volume, mass, or size.