FOSCHINI, LUIGILUIGIFOSCHINI2020-08-272020-08-2720172296-987Xhttp://hdl.handle.net/20.500.12386/26898After the discovery of powerful relativistic jets from Narrow-Line Seyfert 1 Galaxies, and the understanding of their similarity with those of blazars, a problem of terminology was born. The word blazar is today associated to BL Lac Objects and Flat-Spectrum Radio Quasars, which are somehow different from Narrow-Line Seyfert 1 Galaxies. Using the same word for all the three classes of AGN could drive either toward some misunderstanding, or to the oversight of some important characteristics. I review the main characteristics of these sources, and finally I propose a new scheme of classification.ELETTRONICOenArticle10.3389/fspas.2017.00006000428535400001https://www.frontiersin.org/articles/10.3389/fspas.2017.00006/full2017FrASS...4....6FFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation