possible
Able to happen or be done; not impossible.
Possible means something can happen or be done, even if it hasn't happened yet. When your teacher asks if it's possible to finish your project by Friday, she's asking whether you have enough time and ability to get it done. When scientists say it might be possible to grow plants on Mars someday, they mean the laws of nature don't prevent it, even though we haven't figured out how.
The word sits between certainty and impossibility. Rain tomorrow is possible. You flying to school by flapping your arms is not possible. Getting an A on your next test is possible if you study, but there's no guarantee.
Possible often pairs with effort and planning. Building a treehouse is possible if you have materials, tools, and help. Learning to play piano is possible with practice and patience. The opposite of possible is impossible, meaning it absolutely cannot happen or be done.
When someone says “anything is possible,” they usually mean that with hard work and creativity, you can achieve more than you might think. When someone says something is “barely possible” or “just possible,” they mean it's extremely difficult but not quite impossible.