Not being an engineer, that confused the hell out of me, but after about an hour of thinking I think I get it. So here's what I think it means
Find characterisitc impedance of the unterminated cable.
On the source end, terminate it using a connector with an impedance that when added with the source's output impedance will total the characteristic impedance of the cable. So, if the characteristic impedance of the cable is 10, and the source's output impedance is 4, then you'd need a connector with an impedance of 6.
On the destination end, terminate to ____ (this is the part that threw me off; if you terminate the signal wire to ground how does the signal get to the other end? Sorry I'm a noob...)