The Latin root word *plex* means "weave." This Latin root is the word origin of a good number of English vocabulary words, including com[*plex*]ity, per[*plex*]ed, and googol[*plex*]. The Latin root word *plex* is easily recalled through the word du[*plex*], for a "du[*plex*]" is a single building in which two living spaces have been "woven" together.