Bill-rate, or BR$/hr is the dollar-amount per hour charged to a client company for contracting or consulting services. This is the total, end-cost of the contractor as an hourly amount. There are no other fees related to the contractor unless otherwise negotiated (per-diem, reference checking, etc).
From the bill-rate, all employee liabilities including payroll to the contractor, taxes, insurances, other liabilities are paid. The difference between the bill-rate and these total costs is the profit to the agency, also known as gross-profit, or GP$/hr.