Can we say the DL knowledge base is only composed of axioms?

Hi, dear colleagues,

Recently I read some papers of Description Logic, I am confused by something

As we know, a DL knowledge base consists of concepts, roles, individual,
constructs, TBox and ABox,
The TBox contains axioms that make statements about how concepts and roles
related to each other,
the ABox contian statements that asserts properties of individuals by
relating concepts and roles to them,

Is the statement in ABox a kind of axiom?
What's the definition of axiom?
Can we say the DL knowledge base is only composed of axioms?

can someone help me figure it out,
Thank you very much!


-- 
Best Regards!

Jun Fang