Search Result for "d region":
Wordnet 3.0

NOUN (1)

1. the lowest region of the ionosphere (35 to 50 miles up) that reflects low-frequency radio waves;
[syn: D-layer, D region]



WordNet (r) 3.0 (2006):

D region
    n 1: the lowest region of the ionosphere (35 to 50 miles up)
         that reflects low-frequency radio waves [syn: D-layer, D
         region]