Sectarianism refers to division and conflict arising from differences in religious or political beliefs, often leading to discrimination or hostility between groups. It typically manifests in societies where multiple sects or factions exist, such as different branches of a religion or political ideologies. This phenomenon can result in social fragmentation, violence, and a lack of cooperation among communities. Historical examples include the Sunni and Shia divide in Islam or the Protestant and Catholic tensions in Northern Ireland. Understanding sectarianism is crucial for promoting tolerance and peaceful coexistence in diverse societies.