I encountered the following situation in a 1930 census of a household of a family I am researching: In addition to mother (head) and daughter, there is a roomer, and three girls with the same last name (ages 15, 13, and 11) shown as boarders.
What are the definitions of the two terms? (My guess is that this was a foster household for the three girls.) What is the definition of the term "lodger" relative to the preceding? Would these terms be used consistently across all censuses?