That's a great question. In essence, all of these words describe a toilet that doesn't use any water to 'flush', so it's waterless or dry.
However, not all toilets produce compost - some just capture the 'ingredients' that might be composted later, away from the toilet. Generally, they try to keep the solids as dry as possible so often separate the urine in some way. We call these compost toilets (as opposed to composting toilets), but you might prefer just to say waterless or dry. An example of this would be the Separett Tiny, Separett Villa or the Kazuba products.
If the toilet actually does the composting (ie you empty compost at the end of a period of time), then these are composting toilets. These tend to be physically larger (but not always) as they need to contain more material to enable composting to take place. As example of a composting toilet would be the WooWoo GT or the Alectura.
You can also find out more by listening to Episode 2 of our podcast series.