Psalms, Hymns and Spiritual songs.
“There are only a few passages in the New Testament that have a direct bearing on the question of what songs we should sing in worship. Most of them can be found conducting a simple survey of the terms used in the New Testament to express the idea of song. There are only three verb forms, along with their substantives, that need to be considered. The words are psalmos (ψαλμός), ōdē (ὧδή ) and humnos (ὕμνος). They are commonly translated psalm, son and hymn respectively. It almost goes without saying that these three musical terms did not necessarily mean the same thing to new testament readers as they do to us now.”
“The meaning of the religious terms used in the New Testament were condition to a large extent by the usage of those terms in the Septuagint , the Greek version of the Old Testament in common use at that time.”
“Psalmos (ψαλμός) occurs some 87 times in the Septuagint, some 78 of which are in the Psalms themselves, and 67 times in the Psalm Titles.”
Humnos (ὕμνος) occurs some 17 times in the Septuagint, 13 of which are in the Psalms, 6 times in the titles. In 2 Samuel, 1 & 2 Chronicles and Nehemiah there are some 16 examples in which the Psalms are called “hymns” or “songs” and the singing of them is called “hymning”. Philo (d A.D. 40) frequently designates certain Psalms as “hymns”. The historian Josephus also repeatedly alludes to to the Psalms as “hymns”.
Odee (ὧδή ) occurs some 80 times in the Septuagint, 45 of which are in the Psalms, 36 in the Psalm titles.