Marriage of a boy and girl belonging to same religion but different caste is called inter caste marriage. Like marriage between a Brahmin and a Rajput or A Vaishya and a Brahmin will be an intercaste marriage. Intercaste marriage in most of the cases happens to be a love marriage.
Marriage of a boy and a girl belonging to different religion is called inter-religion marriage. Like marriage between a Hindu and a Muslim or a Christian and a Hindu or a Christian and a Muslim will be an inter religion marriage.