1an acceptance that something exists or is true, especially one without proof:his belief in extraterrestrial life [with clause]:a belief that climate can be modified beneficially
something one accepts as true or real; a firmly held opinion:we’re prepared to fight for our beliefs [mass noun]:contrary to popular belief existing safety regulations were adequate
a religious conviction:Christian beliefs [mass noun]:the medieval system of fervent religious belief
2 (belief in) trust, faith, or confidence in (someone or something):a belief in democratic politics
be of the belief that
hold the opinion that; think:I am firmly of the belief that we need to improve our product
beyond belief
astonishingly great, good, or bad; incredible:riches beyond belief
in the belief that
thinking or believing that:he took the property in the belief that he had consent
to the best of my belief
in my genuine opinion; as far as I know:to the best of my belief Francis never made a will