Oral is an adjective. It can mean any of the following:
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Oral is sometimes used as a noun, meaning "an examination that is spoken rather than written."
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Although the adjective verbal is sometimes used in place of oral to indicate that something is spoken rather than written, most linguists use verbal more specifically to mean
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Thus, verbal may refer to that which is written rather than spoken. It is, therefore, a good idea, in order to avoid confusion, to use oral to indicate that something is spoken rather than written.
Link to exercise on oral / verbal.