There are a number of synonyms for the word SIGS, which refers to self-interstitial atoms and/or vacancies in a crystal lattice. Some common synonyms include lattice defects, crystal point defects, and crystal imperfections. Other possible synonyms might include vacancies, interstitials, dislocations, stacking faults, and other types of crystal defects. Overall, these synonyms refer to the same basic phenomenon of crystal lattice imperfections, which can have a range of effects on the material's properties and behavior. Depending on the material and the specific type of defect, SIGS and its synonyms can be important considerations in fields ranging from materials science to geology and beyond.