Each word denotes some phenomenon or object, serves as its sign, as, for example, a sign denoting a bus stop. The word is the result of the activity of our brain. To create a word, one had to find the most important feature of an object or phenomenon and, by this feature, designate it. This sign is always contained in the root of the word.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.