It is such an interdisciplinary subject. Thinking about it - a small characteristic of design, be it the system, structure, methodology, aesthetic expression, functions or forms, can be reflected to most of other subjects in this world.
This series is thus an extrapolation of what is design, its correlation with all its other sibling subjects of this world.

Design is like a language system.
I was chatting with a friend the other day, and she was explaining some Japanese basics to me. Having learnt the hardest Chinese language since before I can remember, my experiences with acquiring English & German, both of which belonging to the Germanic branch of Indo-European languages, has been systematic and taken for granted that both started with learning and reading the alphabetic table.
Her explanation on Japanese language, however, stoke me with a sudden realization that most languages are formed with a structural and component based system. If you’re on the frontline of the fashionable words of design, you’d hear about the term “atomic design” or “design systems” frequently these days. A language can therefore be interpreted as very much similar to the atomic design system that’s at its apogee today. Especially in the context of a Chinese originated language system, the development of which were very much a visual interpretation of the objects themselves. So not only do these languages have a system and atomic structure, it’s carved out of the symbolic meanings such that the visual metaphors takes the precedence.
Take the very famous Chinese character of tree “木”, for example.

Structurally, this is how its formed -

木- One tree is a piece of wood
林- Two trees become a grove
森- Three trees become a forest (3, a number that always indicate a few/multiple in the ancient Chinese)

In which case, the character itself becomes the building blocks of its own meaning.

If you attach the tree to something else, say “李“, one of the common surnames in Chinese, which always referred to as fruits, specifically plums, in ancient Chinese -

木- One tree is a piece of wood
子- Son; the child of something
李- (son under the trees) - Fruit from a tree; plums; a surname;

In which case, the character along with another character forms the meaning of a new character.

Another example is “桃“, peaches, a fruit that always used as a prosperous symbol in Chinese culture:

木- One tree is a piece of wood
兆- Prosperous sigh
桃- (Luck by a tree) - Fruit from a tree; peaches;

In which case, the character along with another character forms the meaning of a new character.

A word is formed by a single character or by piecing two or a few characters together; for example, “天下”

天- sky
下- below / under
天下- (under the sky) - the whole world or realm;

In which case, the character along with another character forms the meaning of a new word/phrase.

Piecing words together, and you get a phrase, a idom or a sentence: “桃李满天下“

桃李- the two fruits that we mentioned previously; used together to indicate the “fruits” at harvest - students or mentees from teachers or mentors;
满- full of, all over the place
桃李满天下- have students all over the world; a phrase used to describe teachers and their generous contributions and values;

In which case, words with its individual meanings or metaphors, forms certain expressions or meanings as a phrase or sentence.

Hence the individual characters can be thought of as the atoms (木); some of which forms a particle (李); some of which forms a substance (林); and particles or substances forms materials and compounds, which builds up and forms the whole world.

Language is amazing.
So is design.