Shared meaning: Both can mean "therefore" or "because." ---"I'm very smart, so I'm in the advanced class." ---"I'm very smart, thus, I'm in the advanced class." ---"I am very smart, therefore I'm in the advanced class." ---"Because I'm very smart, I'm in the advanced class." You'll notice that the word order and punctuation change, but the meaning is more or less the same. Not shared meaning: "So" can also mean "very" (I'm so tired.) "So what?" is an idiom that expresses that you don't care. ("I'm so tired." "So what? You still need to finish this work.") Use: "Thus" is somewhat formal and usually only seen in academic, or other formal writing. You might also hear it in a formal debate or speech. Said out loud, "thus" can sound pretentious. "So" is more casual. It's common in everyday speech and can be too causal for some formal conversations or formal writing. I'm a native English speaker and professional writer and I've never heard of "os." It might just be a typo. Or slang, maybe?

The words "thus," "as," and "so" are commonly used in English but serve different purposes. Here’s a breakdown of their usage: Thus Meaning: "Thus" is often used to mean "therefore" or "consequently." It indicates a result or consequence. Usage: As a result: It shows the outcome of a previously mentioned situation. Example: "He didn't study for the exam; thus, he failed." In this way: It can describe a manner or method. Example: "She mixed the ingredients thus, ensuring the best flavor." To this extent or degree: It indicates the extent of something. Example: "The solution is thus suitable for our needs." As Meaning: "As" has several uses, such as showing a role or function, making comparisons, and indicating time. Usage: Role or function: It shows someone or something's role. Example: "He works as a teacher." Comparison: It is used in comparisons, usually with "as... as." Example: "She is as tall as her brother." Time: It can indicate something happening at the same time. Example: "As I was walking, I saw a friend." Reason: It can mean "because." Example: "As it was raining, we stayed inside." So Meaning: "So" is versatile and can indicate purpose, result, or degree. Usage: Result: It shows the result of an action. Example: "She was tired, so she went to bed early." Purpose: It indicates intention when used with "that." Example: "He worked hard so that he could save money." Degree: It shows the extent or degree of something. Example: "She is so happy." Emphasis: It can emphasize an adjective or adverb. Example: "The movie was so good." Agreement or continuation: It can be used to continue a conversation or agree. Example: "So, what do you think about the plan?"