What is "upachayasthanas"

The term Upachayasthana is derived from the Sanskrit word उपचय which means increase, it also means the entire process of acquisition, assimilation and augmentation or proximate aggregation or increase or gain of nourishment or in growth or in body weight.

In Hindu astrology the 3rd, the 6th, the 10th and the 11th bhavas or houses counted from the Lagna or the Moon are known as the Upachayasthanas, they are known as the houses of growth and expansion.