Daled amot translates most accurately as personal space. Using it in a sentence, one might say, Whether you choose to put on deodorant is your own business, as long as you stay out of my daled amot.
A secondary sense of the word is an area of expertise, as in Dont ask me about quantum physics, thats outside my daled amot.
Daled amot measures about six feet: daled is the Hebrew letter corresponding to the number four, and an amah is the biblical measure of a cubit, the distance from your elbow to your middle fingertip (roughly a foot and a half for most people.) In Jewish law, daled amot is a persons private domain.
Among the ramifications of this definition are that carrying an object a distance of more than four amot in a public domain on Shabbat violates a biblical prohibition; and that a man should not walk more than four amot with his head uncovered.
The Babylonian sage Ulla poignantly declared, Since the day the Temple was destroyed, all that remains for the Holy One, Blessed Be He, in His world are the four amot of halachah (Talmud, Berachot 8a).
The sense seems to be that since the site of Gods permanent dwelling in Jerusalem was erased, God is present in the private sphere within which we act according to His will.
Rabbi AJ Heschel notes that this is hardly a jubilant statement expressing an ideal. We work and pray for the time when Gods presence will return to our communal and national lives, and beyond.