Lao (老) Zi (字): Dao (道) De (德) Jing (經)
Lao (老) Zi (字) is one of the pre-eminent philosophers of ancient China. According to legend he was the keeper of the imperial archives in the ancient capital of Lo Yang. After witnessing what he viewed as a general decline of the society around him, he left the city and rode alone into the western desert. He was stopped at the border by a gatekeeper named Yin Hsi who insisted that he should not (or could not) leave without leaving some explanation of his philosophy. Lao (老) Zi (字) agreed and dictated to Yin Hsi the eighty-one chapters we now know as the Classic Book of Dao and De (道 德 經).
There are innumerable English translations of 道 德 經 and their interpretations are sometimes quite diverse owing to the flexibility of the Chinese language itself. This natural flexibility is enhanced in 道 德 經 by the age of the text as the subtlties of meaning can change over time, the poetic nature of the work which emphasizes conveying meaning in as few words as possible, and the lack of punctuation in the original text.
That said, I offer the following for consideration.
The 道 德 經 is a description or explanation of 道 德 - the "virtuous cycle" or "way of the universe" - the cycle of change that carries the subtle, hidden/unseen unvarying stability of X and the active, energetic, dynamic, and changable force of Y.
In the first section, 老 字 says that within 道 there is an underlying subtle, hidden/unseen, irregular force (非) and a more dynamic, visible and regular force (常). Similarly, what is named identifies the dynamic, changable and apparent (常) as well as the more subtle, stable and less visible (非). 老 字 says heaven and earth originate from the subtle underlying force - nameless while the more active and changable named is the mother of "ten thousand things"
非 常 道
Irregular and Regular
非 常 名
Irregular and Regular
無 名 天 地 之 始
Origin of heaven and earth is nameless
(Regular - Constant - Unvarying)
有 名 萬 物 之 母
Named is the mother of ten thousand things
(Irregular - Dynamic - Changing)
In the second section, 老 字 says the underlying mystery can be sensed from apparent emptiness and that the edge of potential can be sensed from the apparent being. He also says that although the mystery and the edge are called by different names, they come from the same source. Lastly, 老 字 tells us the relationship these forces is a profound mystery - the door to all other mysteries.
常 舞 欲 以 觀 其 妙
Regular emptiness used to sense the mystery
常 有 欲 以 觀 其 徼
Regular being used to sense the edge
此 兩 者同 出 而 異 名
These two things come from the same name but have different names
同 謂 之 玄
Same meaning (source) is a mystery
玄 之 又 玄
A mystery within a mystery
眾 妙 之 門
The door to multiple mysteries