The word "tetranychid" is an interesting term that refers to a specific family of mites. However, if you are looking for synonyms for this word, you may want to consider using alternate terms such as spider mites or red mites. Other synonyms may include false spider mites, feather mites, and flat mites. Additionally, if you are looking for a more general term, you may want to consider using the word "mite" to encompass various types of small arachnids. No matter which synonym you choose to use, it's important to ensure that it accurately represents the specific type of mite you are referring to.