The word "rat" usually refers to a small rodent with a long tail and sharp teeth. It can also mean someone who is a traitor or dishonest. Full definition
The scientists ran an experiment on a group of rats of varying ages, allowing the animals to drink as much sweetened condensed milk as they wanted. (discovermagazine.com)
There's no need to jump into any kind of rat race to sell more books. (thecollegeinvestor.com)
The researchers also saw similar effects in bone repair, with the engineered growth factors showing a much higher deposition of bone tissue in rats with skull defects. (sciencedaily.com)