1) I do not think that either necessarily has anything to do with God or a Higher Power.
2) There are MANY different definitions of both religion and spirituality.
3) Some people tend to group everything that they do not like about religion, leave that behind, and call whatever is left over as spirituality.
4) I have read that people in Europe do not generally have a category of “spirituality”. They see themselves either as religious or irreligious.
5) Some use spirituality as a way to retreat from the messiness of religion and the difficulty of relationships and interactions with other people. Their spirituality is an inward journey of subjectivity without any actual, concrete actions that benefit other people.

I offer the following definition of religion:

Religion is man’s total experience of that which is considered the most important in all of life, is characterized by devotion and commitment to, love and fear of, and joy over this ultimate value, is expressed through private and/or social, symbolic rites, and provides a way of responding to and of understanding the whole of life

Another similar definition is offered by Geddes Maggregor:

Religion is chararacterized by

1) interest in,
2) concern for,
3) encounter with,
4) sense of absence from,
5) sacrificial ove of,
6) commitment to, and
7) joy over,

that which is judged to be more important than anything else in one’s experience and which, so conceptualized, is taken to be a symbol of that which lies at the heart of all possible experience.