The American Heritage® Dictionary of the English Language, 4th Edition
adj. Characterized by relatively low annual rainfall of 25 to 50 centimeters (10 to 20 inches) and having scrubby vegetation with short, coarse grasses; not completely arid.
adj. Somewhat arid, receiving little rainfall but more than an arid area would. Typically defined as 25 to 50 cm or 10 to 20 inches of rainfall annually.
The Century Dictionary and Cyclopedia
See the extract.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. somewhat arid
Word Usage
"The transition regions between deserts and grasslands are sometimes called semiarid deserts (e.g. the Great Basin of the western United States)."