(bound form) a boundary, border, or limit; a place where two areas meet

(bound form) a specific group of people or field of activity shared by professional, social, or personal identity; circles; world

(bound form) a realm or special domain, often used for spiritual or environmental contexts

(biology) the highest primary rank in biological classification, above phylum

(literary) to be adjacent to or share a boundary with

(geology) a chronostratigraphic unit representing the time of an era, below an eonothem and above a system