The Interactive Glossary: Defining the Net
Attribute
An attribute is an addition to an HTML tag that extends or qualifies its meaning. For example you can extend the image tag by including the ALIGN attribute that lets you specify how you want a block of text to line up with an image. With the ALIGN attribute you can align text to the left, right, center, top, middle, or bottom of an image. Another attribute used to extend an image tag is the BORDER attribute that allows you to specify the size of the border in pixels, that appears around an image that is a hotlink.
See: Tags