Square plot is that where the size of all four sides is same. If the size is any side varies within 5%, it still considered as square. Such plots are for not favored for residence, business or other purposes.

However the length of any side is varying within 10%, such plots are also considered as square only.

In a plot if the variation in sizes is more that 10 %, it is called rectangular. Such plots are ideal for residential, shop, office, buildings, factory and the like.