- apology - an expression of regret at having caused trouble for someone; "he wrote a letter of apology to the hostess"
 --1 is a kind of acknowledgment, acknowledgement
 Derived forms: verb apologize1, verb apologise1, verb apologise2 
- apology, apologia - a formal written defense of something you believe in strongly
 --2 is a kind of defense, defence, vindication
 Derived form: verb apologise1 
- apology, excuse - a poor example; "it was an apology for a meal"; "a poor excuse for an automobile"
 --3 is a kind of example, illustration, instance, representative