When we talk about family relationships, we often use the term "related by blood" to indicate a biological connection. However, there are several other words and phrases that can be used to describe this type of relationship. Some synonyms for "related by blood" include "kin", "family members", "blood relatives", "flesh and blood", and "lineage". These terms are all commonly used to describe close family connections that are based on shared genetics and ancestry. While "related by blood" is a straightforward and commonly used expression, these synonyms can add color and variety to your descriptions of family relationships.