There are people who know, it seems, everything in the world, can give an answer to any question, have an opinion on any subject. There are not many of them, but they are. Envious people tease such a person "know-it-all" or "walking encyclopedia". And what are such people actually called?
Sage
At a time when there was no Internet, telephone, telegraph, and books were "written" on the walls of the cave or wooden plates, there was one person who knew the answers to all questions. People came to him from all over the earth and asked, asked … Why does the earth turn? How many stars are there in the sky? What is the acceptable level of alcohol in the driver's blood? Although no, the latter, perhaps, was not asked, but never mind. It is important that this person answered all the questions thoroughly and sensibly and never said: “I don’t know”. People were amazed and called this man a sage, that is, not just smart, but possessing the highest wisdom. In fact, the person was not a sage, he just had knowledge.
Encyclopedist
A person who has extensive and deep knowledge from various fields of science and who knows life well in all its manifestations is today called an encyclopedist. An encyclopedist, like a "walking encyclopedia", knows a lot of things. He is aware of the population of Bangladesh, about the area of the world's smallest country of Nauru, he can instantly convert centners to hectares, knows the diameter of an ostrich egg and at what speed a female jaguar can run.
Erudite
Very similar to the encyclopedist erudite. But, unlike the first, he not only uses the knowledge accumulated by his excellent memory, but is also able to instantly solve the assigned tasks. Not from the category of mathematics. An erudite person can answer almost any question using knowledge plus logical thinking. Even if he is not 100% sure of the correctness of the answer, he will "calculate" the correct answer by eliminating incorrect ones.
Erudition is the depth and breadth of knowledge that arises as a result of the formation and comprehension of various sources. The scholar is able to draw critical conclusions using deductive logic, and seeks to constantly expand his intellectual horizon.
Guru
People who in many countries of the world are called gurus, not only have the deepest knowledge, but also carry a colossal experience, which they readily and happily share with everyone. They not only convey information, but also direct the questioner on the right path. They not only offer people their knowledge, but create a whole system of knowledge and experience transfer.
And the most real sages who really know everything, they are not named in any way, because they modestly declare themselves: "I know that I do not know anything." Maybe close friends call them "dunno"?
