To AhmedElkas19: כנסת by itself means assembly. So for the Knesset I think you would mostly see הכנסת. When you have בית הכנסת it means the house of assembly or more commonly, the synagogue. The word synagogue is from a Greek word also meaning meeting place. Google defines it as, "from Greek sunagōgē ‘meeting,’ from sun- ‘together’ + agein ‘bring.’"