The term 'dividing wall' can be represented by two crossword solutions: 'septum' (6 letters) and 'septa' (5 letters). A septum is a wall or partition that divides a space into two parts, while septa are plural for septum. The term septum is derived from the Latin word saeptum, meaning 'ENCLOSURE' or 'something that encloses'. The term septa is derived from the Latin word saepta, meaning 'DIVIDED'. Both terms are commonly used to refer to walls or partitions that divide a space into two parts.