former (Adjective) — Referring to the first of two things or persons mentioned (or the earlier one or ones of several). ex. "the novel was made into a film in 1943 and again in 1967; I prefer the former version to the latter one"
former (Adjective) — Belonging to some prior time. ex. "our former glory"
former (Adjective) — (used especially of persons) of the immediate past. ex. "the former president"
former (Adjective) — Belonging to the distant past. ex. "former generations"
former (Noun) — The first of two or the first mentioned of two. ex. "Tom and Dick were both heroes but only the former is remembered today"