Indeed, words get muddy.
UART and USART (also supports synchronous communication, haven't seen an application using it though) are lower level designs than what we actually know as serial or rs232 etc. In essence, they are shift registers. Over time more features were integrated in them such as hardware flow control or modem control signals (most popular device at the time). However UART/serial description may be interchangable. The most common chip in hardware serial devices in older PCs was a UART (16550) and the FTDI/prolific chips can be described as UARTs.
Now about the CP2102, I use it to program arduinos and I know that it has modem control signals which for the arduino are used to auto-reset the atmega after programming. For all intended uses that I know of/have used in the past, CP2102 should be able to do the things that FTDI/prolific chips can do. The main difference is that CP2102 is cheeeep, (or probably cloned?) and usually used in lower end devices.