idolum
noun
a mental picture; idea
a false idea, fallacy
Word Origin for idolum
C17: from Latin: idol
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012