Something segmented is made of separate parts that are still joined into one whole. A worm has a segmented body: you can see the rings, but it is one animal. People also call an orange segmented because it pulls apart into pieces that belonged together. A show or a lesson can be segmented if it comes in chunks, one after another. The word is a little more formal than “in pieces,” and it keeps the idea that the bits belong to the same thing, not a pile of leftovers. Though actually, science uses it in a tighter way for animals whose bodies are built in repeating units, while everyday talk uses it more loosely for anything clearly cut into sections. The picture is “parts, but still one thing.”