Definition of "horse race" [horse race]

• A competitive race for horses carrying jockeys; often the subject of betting (noun)
• An exciting and arduous competition (as in a political campaign). (noun)

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• "The Racing Stable Manager/Aspiring Trainer course offers instruction in horse care, training and conditioning, medication procedures and restrictions, horse race procedures such as declarations and scratches and the claiming process, the client-trainer relationship, stable maintenance, and record keeping and scheduling."
• "The substance of virtually all those letters was ignored by the media, which treated the evolving story as more of a horse race between competing claims: “Ban Three-in-One Jab, Urge Doctors After New Fears” and “Doctors Link Autism to MMR Vaccination” one day, “Research Rejects Autism Link with Vaccine” and “Triple Jab Is Safe, Says Medical Chief” the next."
• "At the Games I won the spear-throwing and the jumping, and a silly horse race with little Minyan ponies."