datum level or datum line
- surveying the horizontal plane from which heights and depths are calculated
datum plane(dā′təm, dăt′əm, dä′təm)
- An arbitrary plane used as a base from which to make craniometric measurements.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.