1. A portico or lobby of an early Christian or Byzantine church or basilica, originally separated from the nave by a railing or screen.
2. An entrance hall leading to the nave of a church.

[Late Greek narthēx, from Greek, box, giant fennel, perhaps of Indic origin.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.