respiratory syncytial virus

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An RNA virus that causes minor respiratory infections in adults and bronchitis and bronchopneumonia in children.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A virus causing respiratory tract infections. Abbreviated as RSV.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a paramyxovirus that forms syncytia in tissue culture and that is responsible for severe respiratory diseases such as bronchiolitis and bronchial pneumonia (especially in children)