Believing in or worshipping more than one God. This is in contrast to Christianity which is monotheism – believing in just one God, although there are three distinct beings: Father, Son and Holy Spirit (Deut 6:4; Act 1:4,5; 2 Cor 13:14; 1 Tim 2:5). God forbids His people to have any other God besides Him (Ex 20:3).

See also: God, monotheism, theism, trinity.