A fitted is a cloth diaper that is absorbent, but still requires a waterproof cover. Most are fitted around the leg and waist openings so no folding is required. Many tend to snap, so no snappi, pins, boingo, etc. are required. I have found there are normally newborn fitteds and then one sized fitteds with a snap down rise.

Honestly, to better understand how the different diapers are constructed I suggest checking out the diagrams on manufacturers sites such as Thirsties.