"Root" in linguistics refers to the basic building block of a word. Think of a puzzle, where each piece represents a small part of a word. Roots are the biggest pieces that all other smaller pieces connect to in order to create a complete word.
For example, the word "walking" has the root "walk." This root is what determines the basic meaning of the word. We can add other pieces to it, like "ing" to make it into a verb or "er" to make it into a noun, but without the root "walk," the word would not exist.
Roots are like the foundation of a building. Without a strong foundation, the rest of the building will not stand up. Similarly, without a solid root, a word cannot be formed properly.
Linguists study roots to understand the origins of words and how languages have evolved over time. By examining the roots of different languages, they can trace the history of human communication and cultural exchange. So, basically, roots are the building blocks of words that help us understand language and culture better.