The HTML height attribute specifies the height of an element. It can be used on various elements, including but not limited to <img>, <iframe>, <embed>, <video>, and <canvas>, to directly define how tall the element should be displayed. The value of the height attribute can be specified in different units, such as pixels (px) or percentages (%), depending on the context and the specific element it's applied to. When used with images, for example, specifying the height helps the browser to allocate space on the page before the image is fully loaded, which can improve the layout stability during loading. It's important to note, however, that setting the height without considering the aspect ratio of content like images or videos might lead to distortion. Therefore, it is often recommended to use this attribute in conjunction with the width attribute to maintain the original aspect ratio of the content.