WCDMA 1700 is a mode, which in this context means a combination of a technology and a frequency band. In this case, it is WCDMA technology and the AWS frequency band.
In the US, WCDMA 1700 is what T-Mobile USA uses for 3G service.
The 1700 (AWS) band is also sometimes referred to as "band IV", particularly when WCDMA technology is involved.
The AWS frequency band has two parts, one near 1700 MHz and another near 2100 MHz. To avoid confusion with Europe's (quite different) "2100" band, Phone Scoop refers to AWS simply by the 1700 part, hence "WCDMA 1700".
It is important to not confuse WCDMA with CDMA.