IOU is a 3-letter acronym that can mean: · A note and acknowledgment of personal debt (from the phrase "I owe you" or "I owe unto") · A band that three members of Westlife were once in · The title of a song by the Canadian Indie Rock band Metric from the album Old World Underground, Where Are You Now? · Illuminati University, a campaign setting for the GURPS roleplaying game · Investor-Owned Utility · A mobile phone service provided by both Vodafone New Zealand and Vodafone Ireland. A customer can request an interim pay-as-you-go credit of NZ$2 or ?2 respectively, which is repaid when the credit is recharged. · I.O.U., A clothing brand that was popular in the 1990's. It stood for Innovative, Original and Unique. IOUIOU