What is an ORV?

"ORV" is short for "Oceanographic Research Vessel"

"Oceanographic" comes from the word "oceanography"

o·cean·og·ra·phy  (ō'shə-nŏg'rə-fē)
n.   The exploration and scientific study of the ocean and its phenomena. 

(The American Heritage® Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004. 30 Aug. 2007)

"Research" is a search for knowledge.

 A "Vessel" is a ship.

ORV's are ships that provide transportation for scientists studying the ocean.