Labor means work, especially physical work that requires effort and energy. When farmers labor in their fields, they're planting seeds, pulling weeds, and harvesting crops. When construction workers labor on a building site, they're lifting heavy materials, operating machinery, and working with their hands and bodies to create something.

The word often suggests sustained, demanding work rather than quick, easy tasks. You might say someone labored for hours to build a treehouse or labored over a difficult essay, revising it again and again until it was right. The effort itself is the labor, whether it produces a physical structure, a finished piece of writing, or a solved problem.

Labor also refers to workers as a group. When news reports discuss labor and management negotiating, they mean employees and their bosses trying to agree on wages and working conditions. A labor union is an organization that represents workers. The American holiday Labor Day celebrates the contributions and achievements of workers throughout the country's history.

Related words include laborious, meaning requiring a lot of work (a laborious task), and laborer, meaning someone who does physical work for pay. When you labor at something difficult, you're putting in serious effort to accomplish it.