oxford dictionary-
1- a particular system of faith and worship.
2-a pursuit or interest followed with great devotion.

"evolution is promoted by its practitioners as more than mere science.evolution is promulgated as an ideology,a secular religion-a full fledged alternative to christianity,with meaning and morality.i am an ardent evolutionist and an ex-christian,but i must admit that in this one complaint-mr gish is but one of many to make it-the literalists are absolutely right.evolution is a religion.this was true of evolution in the beginning,and it is true of evolution still today.....
evolution therefore came into being as a kind of secular ideology,an explicit substitute for christianity"
ruse,m   national post ppb1 b3 b7    13/5/2000

so there you have it- a dictionary entry,and an admission.