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An expert witness is someone who has special education, knowledge, training or experience in a specific field. They are often called as a witness in legal cases and may receive compensation for testifying.
An Expert Aviator is called an "Ace".
A cultures expert is called an ethnologist.
what ia an expert pilot called
A bully expert is called a bullnation
A grammar expert is called a grammatician or a grammarian.
Expert advice or expert guidance.
An expert in his field is often called a specialist or an authority.
an expert on China is called a sinologist.
A cultures expert is called an ethnologist.
Don't know the origin of the word, but a snake expert is called a herpetologist.