faith
Strong belief or trust in someone or something unseen.
Faith is belief or trust in something without needing complete proof. When you have faith in your best friend, you trust they'll keep your secrets even when you're not around to check. When a coach has faith in a struggling player, she believes the player will improve even before seeing results.
The word often describes religious belief: believing in God or following religious teachings. People of different faiths (Christians, Jews, Muslims, Buddhists, and others) hold deep convictions about spiritual truths that can't be proven like a math equation. Religious faith gives many people purpose, comfort, and a sense of connection to something greater than themselves.
But faith isn't only religious. Scientists have faith that careful experiments will reveal nature's secrets. An inventor has faith that a new design will work. Your parents had faith in you before you could do much of anything at all. Faith means trusting in possibilities you can't yet see.
Faith differs from wishful thinking because it's based on something: past experience, a person's character, or deep conviction. You might have faith that spring will come because it always has. You keep faith with someone when you stay loyal to them. And when you take something on faith, you accept it as true because you trust the source.