The introduction begins with the definition of what we mean by “single” in this context, then looks for Greek and Latin vocabulary that carries that meaning, as well as similar meanings in other ancient languages. The modern sense is “a person not married or in an exclusive relationship.” But cross-culturally, the vocabulary of singleness may emphasize celibacy, solitariness, or loneliness, or distinguish the state for men and women. But in modern international use, the untranslated English word “single” has come into use as a general and neutral term.