Is it ensure, insure, or assure?
"short hymn," early 13c., from Latin canticulum "a little song," diminutive of canticum "song" (also a scene in Roman comedy enacted by one person and accompanied by music and dancing), from cantus (see chant (v.)).
((from Latin canticulum, diminutive of canticum, "song"), a scriptural hymn text, used in various Christian liturgies, that is similar to a psalm in form and content but appears apart from the book of Psalms. In the Old Testament there are at least a dozen such hymns (called the cantica minora, or lesser canticles). A few of these are known to have been used by the Jews, in the services both at the Temple and at the synagogue. Of several New Testament canticles (the cantica majora, the greater, or Evangelical, canticles), three are used daily in the Roman Catholic rite: Benedictus (Luke 1: 68-79), the canticle of Zechariah, at Lauds; Magnificat (Luke 1: 46-55), the canticle of the Virgin Mary, at Vespers; and Nunc Dimittis (Luke 2: 29-32), the canticle of Simeon, at Compline. The Book of Common Prayer of the Church of England applies the word canticle only for the Benedicite, but, in practice, the term has been adopted for the psalms and hymns used daily in the Morning and Evening Prayers. A number of other texts not originating in the Bible are also generally regarded as canticles; these include the Lord's Prayer, the Apostles' Creed, and the Te Deum, which has been one of the canticles of Morning Prayer in Anglican Church music since 1549. The term canticles is sometimes used as an abbreviation for Canticum canticorum (Song of Songs), an alternative name for the Song of Solomon, selections from which have been frequently used in the composition of motets.