Great. I hate the Langchain's author avatar and the documentation with a passion. The documentation failed at explain the "terms" being used. What's an agent ?

Great. I hate the Langchain's author avatar and the documentation with a passion. The documentation failed at explain the "terms" being used. What's an agent ? What does "langchain" mean ? Some minimal example that works without little efforts ? .. Nothing's there. The feeling is that, he doesn't respect software engineer who's new to AI to some extend.