Is it ensure, insure, or assure?
late 14c., "act of bringing together," from Old French collation (13c.) "collation, comparison, discussion" (also "a light supper"), from Latin collationem (nominative collatio), noun of action from collatus, irregular past participle of conferre "to bring together" (see collate). The word has had many meanings over the centuries. As the title of a popular 5c. religious work by John Cassian, "Collation" was sometimes translated into Old English as Þurhtogenes.