The basic rate means the lowest/standard level on any monetary scale, particularly relevant for things like taxation, pricing, charges, and so on.
The basic rate equates to the lowest/standard level on any financial scale, that is payable by someone, i.e. the borrower/customer. This is applicable for taxation purposes as well. For example, you may have heard of a term called the base tax rate on something, which increases with the addition of any special levy/cess. The same equates to the pricing of anything or the interest charged on something. This is the definition of basic rate in a nutshell.
The basic or base rate is the minimum rate of interest charged by the RBI and Indian banks cannot lend to customers below this rate. This applies for home loans as well. It may apply for the taxation rate. At the same time, it could mean the basic rate for any property or supplies in the real estate sector, minus taxes, cess, and other charges.