principal vertical circle

principal vertical circle

[′prin·sə·pəl ′vərd·ə·kəl ‚sər·kəl]

(geodesy)

The vertical circle through the north and south points of the horizon, coinciding with the celestial meridian.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.