Definition of viroid
: any of two families (Pospiviroidae and Avsunviroidae) of subviral particles that consist of a small single-stranded RNA arranged in a closed loop without a protein shell and that replicate in their host plants where they may or may not be pathogenic
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Merriam-Webster unabridgedWords at Play
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Time Traveler for viroid
The first known use of viroid was in 1971
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