Although the Hebrew Bible is very much concerned with rituals, the word itself (along with ceremony and rite), rarely occur in the standard English translations. Moreover, there is no word in biblical Hebrew that is the precise equivalent of any of these terms. Peter Leithart speculates about the reason:
A great deal of the Pentateuch, after all, is concerned with what theologians call “ceremonial law,” what we would instinctively identify as “ritual” matters. . . . [T]he lack of a specific biblical vocabulary of “ritual” raises the suspicion that the Bible does not isolate ritual as a distinct sort of activity in the way that we do. In anthropological theories of ritual, it is often assumed that ritual activities are symbolic and expressive forms of action, distinct from the functional and pragmatic activities of daily life. Almost by definition, “ritual” has come to mean “merely symbolic” or “non-functional.” The fact that the Bible does not employ a distinct vocabulary of ritual suggests that it assumes continuities between ritual and other types of activity that moderns find hard to grasp.
Read more on First Things: http://www.firstthings.com/blogs/leithart/2016/04/biblical-terms-for-ritual