You can't from this information, because "pixel pitch" is: sensor length divided by number of pixels along that dimension. You don't have sensor size — the 2/3" designation is generally around 11mm diagonal, but can vary in specifics.
It's possible that "pixel size" in this spec also means "pixel pitch", but it's also possible that that's been measured in a different way. The given number lines up reasonably well (given a 1920×1200 sensor, that'd be a diagonal of about 10.9mm).
Depending on your needs, that might be close enough. Do you have the exact dimensions of the imaging area from which the 1920×1200 readout is produced? If you need more precision, you'll need that.
From your comment:
Are pixel size and pixel pitch the same thing?
Not necessarily: pixel pitch is measured from center to center, and it's possible that there is a small gap between each pixel so this would be different from pixel size. However, if your purpose in knowing this number is a general sense of the light-collection area of each pixel in comparing camera specs, it's close enough that it doesn't matter.
If your purpose is precise measurement, you probably need to actually do in-the-field measurements based on your actual total system in practice rather than making theoretical assumptions. This is especially the case when the tool you are buying is made and marketing as a device for making images but you want to use it instead as a measuring device.