Of sostre doesn't appear much, however sastre has meaning in dictionaries. Although my words do not come from thorough research, I can tell you that surnames usually came from some legal family or the place in which the family lived. Over time a surname changes, letters are added or moved them one of them. Assuming this to be the case, sastre comes from latin and means " 34 scissors; Also we should add that some sites where it is believed that the family originated are: Wales of the United Kingdom, France, England, or Italy.