n.
  - a religious group or faction regarded as heretical or as deviating from orthodox tradition. 
▸often derogatory a group that has separated from an established Church; a nonconformist Church.
 - a group with extreme or dangerous philosophical or political ideas.
 
 
  Etymology
  ME: from OFr. secte or L. secta, lit. ‘following’, hence ‘faction, party’, from the stem of sequi ‘follow’.