Photosites: This is where the action is in a digital camera. While you might think that an image sensor is comprised of millions of pixels, in actuality, it's made up of photosites. Each photosite contains a light-sensing device (called a photodiode) and a storage area to hold the charge created by the photodiode. When light hits the photodiode, it converts the light into electrons, or a charge. The more light that hits the photodiode, the greater the charge. Further processing either at the photosite or elsewhere in the camera turns this charge into digital data that, in turn, is combined with other photosite data to create a pixel.
Picoliter: Inkjet printer manufacturers use this term to describe the droplets of ink that are produced from the print head. Printers don't print pixels on the page; they use droplets to simulate the colors and tones contained in the image file. A picoliter is a millionth of a millionth (or a trillionth) of a liter. It's a measurement of volume, not of area. The area that's covered by a picoliter of ink depends on many factors, including the formulation of the ink; smaller droplet sizes usually translate into better photo-quality tones, gradations and colors.