truism (n.)

• abstraction
• aphorism
• apothegm
• axiom
• banality
• bromide
• cliche
• commonplace
• dictate
• dictum
• formula
• generalization
• gnome
• gospel
• law
• maxim
• moral
• platitude
• postulate
• principle
• proposition
• rule
• shibboleth
• tag
• theorem
• truth
• verity