MOS = Metal Oxide Silicon
CMOS = Complementary Metal Oxide Silicon
They indicate the semiconductor process use to fabricate the sensors - multiple sensors are produced on a silicon wafer.
It's the same technoloy that is used to make integrated circuits (ICs) and transistors.
Now MOS and CMOS are probably the same in this case; the other normally used type of sensor process is called Bipolar (use in CCD or charge coupled device sensors) and uses a different type of process (but still made from wafers that start life as pure silicon wafers).
The 1/6 and 1/4 inch is telling you the physical size of the sensor.
Example :
http://www.spectek.com/pdfs/imaging/...Brief_K12A.pdf
I've tried to keep it simple.
I actually work for an IC manufacturer; we do not make image sensors - but we do make other ICs that can form the imaging heart of a camera or camcorder (they are connected to the sensor).