The grammatical form of the word “Tawy” is that of a “dual”. In the ancient Egyptian language, the dual was a number between the singular and the plural. It was never used for chance groupings of two items, but only for pairs: groups of two that by their nature can only consist of two elements. Characteristic examples are a person’s two arms, two legs, two ears, and two eyes. The very concept of the dual as a grammatical number was probably derived from this remarkable feature of the human body - as decimal arithmetics were derived from the fact that we have ten fingers. Given this limited area of application of the dual, it is better translated with “both xxx”, than “the two xxx”: “both legs”, rather than “the two legs”.

An automatic consequence of a pair is, that its members belong together, and together form a unity. Our legs belong together, and they form a unity inasmuch as they can only operate effectively in cooperation: to walk we need both legs, as we need both hands to work. Another consequence of a pair is, that it is complete. When a man has two arms and two legs, he is complete - arm-wise and leg-wise.

So to refer to Tawy / Both Lands was to acknowledge that Upper and Lower Egypt belonged together, formed a unity together, and together were complete.