An HTML table is a structured way to display data on a webpage using the Hypertext Markup Language. It consists of rows and columns, where each row is defined by the `<tr>` tag, and each cell within a row is defined by the `<td>` tag. Tables can also include headers, which are created using the `<th>` tag, making it easier to understand the data presented. Tables are useful for organizing information such as schedules, lists, or comparisons. They can be styled with CSS to enhance their appearance, allowing for better readability and visual appeal. Overall, HTML tables are a fundamental tool for web developers to present data clearly.