1.NounAn expression of remorse or regret for having said or done something that harmed another: an instance of apologizing (saying that one is sorry).
"What he said really hurt my feelings, but his apology sounded so sincere that I couldn't help but forgive him.; The CEO made a public apology for the scandal, and promised full cooperation with the authorities."
2.NounA formal justification, defence.
"the Apology of Socrates"
3.NounAnything provided as a substitute; a makeshift.