They are usually made up of the same material and often have similar marking on them. True they are different sizes and shapes and have different uses, but when it comes to dreams they are still remarkably similar because of what they represent. This is because the dream meanings of them are quite similar.
Dreaming of dominoes means that you are worried about your health and your age, as well as your general mortality. The bones in dominoes represent your real bones or the parts of yourself that you see aging along with you. A dream like this that forces you to confront your mortality can be extremely distressing at first but you need to realize that this thing happens all the time, and you also need to realize that you are in fact mortal and you will die one day. Many people are not ready to accept this even when they get old so a dream about dominoes like this would force them to confront that thought and start to ponder what it means to be so old.
Basically dominoes are essentially just stand-ins for the idea of gambling also. To have a dream about dominoes means you are thinking about gambling. Dominoes are also used to build domino chains which can be knocked over and in their being knocked over, will come to make a new picture or come to form the shape of something. If you dream about dominoes it could mean that you are in the middle of an intricate procedure that will one day soon begin to show fruit. Keep it up and you will succeed without issue.