"Vegetarian," in a lesser-known sense of the word, refers to an ethnicity. Like other more commonly acknowledged minority groups, vegetarians are united by certain elements in their physical makeup (in this case, a general insufficiency of nutrients, such as iron and protein), and a shared heritage (vegetarians commonly view non-meat-eaters as their forefathers). Vegetarian, like, for example, "hispanic," refers to a large group of people who share a similar outlook on the world; this concept of possessing a common perspective is characteristic of ethnic groups. While members of other ethnic groups may share commonalities such as skin color and language, vegetarians share more internal commonalities, like the absence of certain foods being digested within their bodies.
Taken from the 2020 Census:
Please indicate your ethnicity using the options below.