[ eyhuh-rahy-zuhn ]
/ ˈeɪ həˌraɪ zən /
the topsoil in a soil profile.
QUIZ YOURSELF ON THESE WORDS FROM BROWN GIRL DREAMING!
Visualize yourself passing this quiz on words from Jacqueline Woodson’s exquisite verse novel “Brown Girl Dreaming,” and then take the quiz to prove you can do it! (Because you can.)
Question 1 of 10
What does “barren” mean?
Also called zone of leaching .
Origin of A horizon
First recorded in 1935–40
Words nearby A horizon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020
British Dictionary definitions for A horizon
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
Scientific definitions for A horizon
In ABC soil, the uppermost, darkest zone that is rich in organic matter. The upper section of the A horizon usually contains humus along with plant and animal matter in varying stages of decay. The middle section usually contains a high concentration of quartz or other minerals that remain following the leaching away of clay, iron, and aluminum. The lower section is typically transitional in nature between the A horizon and the B horizon. Also called zone of leaching
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.