oxidation-reduction indicator
— Noun
– English
～ an indicator that shows a reversible color change between oxidized and reduced forms
over-refine
— Verb
– English
～ refine too much or with excess of subtlety; "He is overrefining this matter"
oil refinery
— Noun
– English
～ a refinery for petroleum
off-axis reflector
— Noun
– English
～ a reflecting telescope with the mirror slightly tilted to throw the image to the side where it can be viewed
oesophageal reflux
— Noun
– English
～ reflux of stomach contents into the esophagus
Osmunda regalis
— Noun
– English
～ large deeply rooted fern of worldwide distribution with upright bipinnate compound tufted fronds
on a regular basis
— Adverb
– English
～ in a regular manner; "letters arrived regularly from his children"
organized religion
— Noun
– English
～ an institution to express belief in a divine power; "he was raised in the Baptist religion"; "a member of his own faith contradicted him"
Ononis repens
— Noun
– English
～ European woody plant having pink flowers and unifoliate leaves and long tough roots; spreads by underground runners
on request
— Adverb
– English
～ on the occasion of a request; "advice was free for the asking"
operations research
— Noun
– English
～ research designed to determine most efficient way to do something
ohmic resistance
— Noun
– English
～ a material's opposition to the flow of electric current; measured in ohms
Ottorino Respighi
— Noun
– English
～ Italian composer remembered for his symphonic poems (1879-1936)
October Revolution
— Noun
– English
～ the coup d'etat by the Bolsheviks under Lenin in November 1917 that led to a period of civil war which ended in victory for the Bolsheviks in 1922
Oedipus Rex
— Noun
– English
～ (Greek mythology) a tragic king of Thebes who unknowingly killed his father Laius and married his mother Jocasta; the subject of the drama `Oedipus Rex' by Sophocles
order Rhamnales
— Noun
– English
～ an order of dicotyledonous plants
order Rheiformes
— Noun
– English
～ a ratite bird order: birds intermediate in characteristics between ostriches and emus: recent and extinct rheas
order Rhoeadales
— Noun
– English
～ an order of dicotyledonous plants
order Rhynchocephalia
— Noun
– English
～ tuataras; extinct forms from middle Triassic
Omani rial
— Noun
– English
～ the basic unit of money in Oman