understratum

(redirected from understratums)
Also found in: Medical.

un·der·stra·tum

 (ŭn′dər-strā′təm, -străt′əm)
n. pl. un·der·stra·ta (-strā′tə, -străt′ə) or un·der·stra·tums
A substratum.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

understratum

(ˈʌndəˌstrɑːtəm)
n, pl -ta (-tə) or -tums
(Physical Geography) the layer of soil underneath the soil on the surface; a substratum or subsoil
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014