of a sudden
— Adverb
– English
～ happening unexpectedly; "suddenly she felt a sharp pain in her side"
Ozark sundrops
— Noun
– English
～ evening-opening primrose of south central United States
ocean sunfish
— Noun
– English
～ among the largest bony fish; pelagic fish having an oval compressed body with high dorsal and anal fins and caudal fin reduced to a rudder-like lobe; worldwide in warm waters
Office of Intelligence Support
— Noun
– English
～ agency that oversees the intelligence relationships of the Treasury's offices and bureaus and provides a link between the Intelligence Community and officials responsible for international economic policy
operating surgeon
— Noun
– English
～ a physician who specializes in surgery
open-heart surgery
— Noun
– English
～ heart surgery in which the rib cage is spread open, the heart is stopped and blood is detoured through a heart-lung machine while a heart valve or coronary artery is surgically repaired
Ordnance Survey
— Noun
– English
～ the official cartography agency of the British government
Orthotomus sutorius
— Noun
– English
～ tropical Asian warbler that stitches leaves together to form and conceal its nest
occipitomastoid suture
— Noun
– English
～ the suture between the occipital and the temporal bones; a continuation of the lamboid suture
Otto Neumann Sverdrup
— Noun
– English
～ Norwegian explorer who led expeditions into the Arctic (1855-1930)
Okefenokee Swamp
— Noun
– English
～ a large swampy area of northeast Florida and southeast Georgia
on-off switch
— Noun
– English
～ a hinged switch that can assume either of two positions
on/off switch
— Noun
– English
～ a hinged switch that can assume either of two positions
organic brain syndrome
— Noun
– English
～ mental abnormality resulting from disturbance of the structure or function of the brain
order Synentognathi
— Noun
– English
～ order of fishes having spineless fins; needlefishes; sauries; flying fishes; halfbeaks
operating system
— Noun
– English
～ (computer science) software that controls the execution of computer programs and may provide various services
octal numeration system
— Noun
– English
～ a positional system of numeration that uses octal digits and a radix of eight