When it comes to our extended family, it's important to address each member with the appropriate title or relationship term. While "parents-in-law" is a well-known term, there are several other synonyms that can be used to refer to one's spouse's parents or one's parent's spouse. Some of these synonyms include "in-laws," "father/mother-in-law," "second parents," "bonus parents," "stepparents," and "extended family." These terms are used depending upon the context, cultural traditions, and the level of formality required. Ultimately, it's important to respect one's in-laws and address them in a manner that is appropriate and comfortable for everyone involved.