Go to MSN Homeencarta®
Dictionary
Find
in
Dictionary
Thesaurus
Translations
ABCDEFGHIJKLMNOPQRSTUVWXYZ
Click to move up the list of words
ionise
ionization
ionization chamber
ionization potential
ionize
ionizing radiation
ionone
ionophore
ionosphere
ionospheric wave
iontophoresis
IOOF
iota
iotacism
IOU
IOW
Iowa
Click to move down the list of words
Also available:

World English Dictionary
Dictionnaire Français

ionosphere
i·on·o·sphere [ ī ónnə sfr ]


noun 
Definition:
 
ionized layers in upper atmosphere: four layers of the Earth's upper atmosphere in which incoming ionizing radiation from space creates ions and free electrons that can reflect radio signals, enabling their transmission around the world
[Early 20th century. <ion]

i·on·o·spher·ic [ ī ònnə sfrik, ī ònnə sférrik ] adjective
i·on·o·spher·i·cal·ly adverb
Encarta® World English Dictionary [North American Edition] © & (P)2009 Microsoft Corporation. All rights reserved. Developed for Microsoft by Bloomsbury Publishing Plc.
Advertisement
© 2009 Microsoft