Definition of ironclad. 1  1 : sheathed in iron armor âused especially of naval vessels. 2  2 : so firm or secure as to be unbreakable: such asa : binding an ironclad oathb : having no obvious weakness an ironclad case against the defendant.
Best Answer: CR means a credit. If this appears on the balance due line of your statement, it means that you owe nothing and that you are that much ahead of future charges and no payment or acknowledgment is needed.
Definition of cred. : credibility; specifically : the ability to gain acceptance as a member of a particular group or class used â¦ his new street cred to develop contacts â Dale Keiger.