The origin of this word is Hindu and Buddhist. It is a word or sound that is repeated as an aid to concentration in meditation. Common forms include Kirtan, Zikr and Dhikr
This is a widely enjoyed practice generally shared in a group of people by many faiths, particularly Hindu, Islam, Christianity in the form of Gregorian Chants and to some extent, what is now considered within the realm of New Thought. Focus is placed on communion with on God or Divine Spirit as defined by you and is an expression of devotion. In a general sense what is said and thought about can be viewed as devotional regardless of your Spiritual Path.
Technically defined through the sacred practice of Kirtan and Zikur, repetitiously chanting the names of God/Goddess from ancient India, Persia and adjacent areas is a musical meditation and yogic adventure deep into the essence of Bhakti---the yoga of the Heart, the yoga of Love...
Thinking about expressing your love of Spirit as you define it eliminates the need to consider Kirtan to be defined as a literal translation of the words and their origins.
One example can be found here.
Govindas and Radha are California-based bhakti yogis, kirtan singers, and as their spiritual names suggest, "servants of the Divine". They are a husband and wife team with great love and devotion for the Divine, their Guru, eachother, and traditional yogic practices of India - This is the essence which is reflected and transmitted through their teachings and music.