IOU
(redirected from I.o.u.)Also found in: Dictionary, Thesaurus, Idioms.
IOU
a corrupted abbreviated form of the words ‘I owe you’. It is a written acknowledgement of a debt. It is not a negotiable instrument, like a cheque, but maybe founded upon in court to make recovery of the sum more simple.Collins Dictionary of Law © W.J. Stewart, 2006