An endeavor is a serious effort to achieve something important or difficult. When scientists endeavor to cure a disease, they commit years of research and experimentation to reach their goal. When an athlete endeavors to make the Olympic team, she dedicates herself to intensive training and practice.

The word carries a sense of determination and purpose. You wouldn't say someone endeavors to tie their shoes, that's too simple and ordinary. But you might say a class endeavors to raise money for new playground equipment, or a writer endeavors to finish her novel. The word fits situations where success isn't guaranteed and real effort is required.

Endeavor can work as either a verb or a noun. As a verb, it means to try hard: “We will endeavor to solve this problem.” As a noun, it describes the project or mission itself: “Building the treehouse was quite an endeavor.”

When you endeavor to do something, you're making a genuine commitment to give your best effort, accepting that the goal might take time and persistence to reach.