noun

1. Mental acceptance of a claim as true.

   “It's my belief that the thief is somebody known to us.”

2. Faith or trust in the reality of something; often based upon one's own reasoning, trust in a claim, desire of actuality, and/or evidence considered.

   “Based on this data, it is our belief that X does not occur.”

3. Something believed.

   “The ancient people have a belief in many deities.”