From Longman Dictionary of Contemporary Englishdebt of gratitude/thanksdebt of gratitude/thanksTHANKthe fact of being grateful to someone who has helped you I owe a debt of gratitude to my tutors. → debt
Examples from the Corpus
debt of gratitude/thanks• In addition to that great teacher of prayer, there were others to whom I owe a debt of gratitude.• We all owe Solly a deep debt of gratitude for his services to the cause of jazz for so many years.• The present writer owes him a particularly deep debt of gratitude.• We all owe him a great debt of gratitude, and we wish him well.• Some say it is because of Baba Firdaus and his holy life, others say because Amanullah Khan paid his debt of gratitude.• Their varied tasks in the Library have all contributed to its success and we owe them a very real debt of gratitude. 