Final answer:
Homophily is the term that describes Thomas looking for social characteristics similar to Susan's when he married her.
Step-by-step explanation:
The term that describes Thomas looking for social characteristics similar to Susan's when he married her is homophily. Homophily is the tendency for people to form social networks, including friendships, marriage, and other types of relationships, with others who are similar to them in background, attitudes, and lifestyle. This means that people are more likely to be attracted to and form relationships with those who share common traits and interests.