The dominant, pervading spirit or character that we call an ethos can be identified in political parties, hospitals, sports bodies, or trade unions. It is also found in every place of work and evidence is emerging of the importance of ethos in successful companies and organisations.
When people speak of school spirit, they are referring to an important aspect of the ethos of a school. The explicit aspect of school ethos is captured in the French phrase for it, la philosophie de l'ecole.
The still fashionable term "hidden curriculum" also captures something of what is meant by ethos. Although rarely to the fore of the consciousness of teachers and pupils, the ethos of a school is often readily perceptible to visitors.
Sometimes it is suggested in the prominence given to symbols - symbols of religious practice or symbols of patriotism/nationalism, of sporting, artistic and academic endeavour, of civic and community involvement.
One very striking symbol of ethos is the school uniform. It says much more about the real ethos of the school than claims in mission statements about respecting individuality.
A religious ethos is the default ethos of most Irish schools but this is a contingent rather than a necessary aspect of the concept. In other words, ethos need not, in principle, imply anything religious.
Many positive values are part of the ethos of all educational institutions, religious and secular alike.
A sense that education is not merely a matter of academic success and a concern for the disadvantaged may be part of the vision of a religious school, but these values and commitments are shared with many schools.
Likewise mission statements about religious ethos which do not extend beyond platitudes about developing "the whole person" or a "rounded person" say little that anyone could possibly disagree with.
The problem is not with the aspirations but rather with how the human development implied is to be interpreted. After all, who would be against the development of persons who are "rounded", at least in the metaphorical sense?
If we try to unpack the terms "whole person" or "rounded person" we shall discover crucial disagreement about whether they include a religious dimension.
This dimension brings us to what is the defining character of a religious ethos. Religion provides a way of apprehending the world that informs the whole life of believers and provides the spring of moral commitments to act in ways that are consistent with realising this ultimate destiny.
Therefore, a school with a religious ethos aims to foster in young people a commitment to particular beliefs, convictions and attitudes, and these are reinforced as a matter of policy.
Within ecumenical schools (e.g. joint Anglican/Catholic) the truth-claims of religion are accepted and promoted as part of the school's ethos but religious faith is not associated with either of the denominations involved.
Within multi-denominational schools, the belief systems of all are respected and tolerated, and arrangements are usually made to provide denominationally-specific religious education for the children of parents who request it. The values of tolerance rather than any substantive beliefs define the ethos of these schools.
Non-denominational schools, by contrast, eschew religion altogether, although pupils may study religion as a cultural or sociological phenomenon.
The school is conceived as a secular space which is agnostic or neutral, concerning the truth-claims of religion, and the provision of religious education - in the sense of fostering religious belief and practice - is precluded.
By contrast, faith shapes significantly the whole culture of religious schools. Christianity, for example, is not simply the placing of an icing of additional, spiritual values on a neutral cake of culture.
It is not that there is a Christian mathematics, science, geography or history but rather that Christians conceive of these and of other areas of the curriculum as the response of the human mind to different aspects of God's creation.
In a sense a religious school resembles a church or place of worship and this resemblance is central to the notion of a religious ethos. This does not prevent such schools being hospitable to children of those who do not share the religious beliefs in question.
But it is best to be honest about the character of religious ethos rather than presenting it as a mishmash of well-meaning sentiments.
Dr Kevin Williams is head of education (graduate studies) at the Mater Dei Institute in Dublin and former president of the Educational Studies Association of Ireland