beaver
noun
a large, amphibious rodent of the genus Castor, having sharp incisors, webbed hind feet, and a flattened tail, noted for its ability to dam streams with trees, branches, etc.
Used to describe an ongoing action or continuous state that was happening at a specific time in the past.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Meanwhile, Crick was beavering away throughout the day.
From The Guardian ● Nov. 12, 2012