ARIA label (aria-label) is an attribute defined in the WAI-ARIA (Web Accessibility Initiative - Accessible Rich Internet Applications) specification that provides an accessible name to UI elements. It is used to provide text information for elements without visual labels, serving as a cue for screen readers when announcing elements.

aria-label is particularly effective for icon-only buttons, navigation landmarks, and other elements where the design conveys meaning visually but lacks text information. For example, if a search button contains only a magnifying glass icon, adding aria-label="Search" communicates the button's purpose to screen reader users. Similarly, when a page has multiple <nav> elements, aria-label="Main navigation" and aria-label="Footer navigation" help distinguish them. ARIA accessibility guides cover these topics in detail.

Related attributes include aria-labelledby (references text from another element) and aria-describedby (references supplementary descriptions). aria-label specifies text directly on the element, while aria-labelledby references existing element IDs. When appropriate text already exists on the page, aria-labelledby is preferred; aria-label is used when no such text exists.

An important principle is that ARIA usage should be limited to cases where native HTML labeling (<label> elements, alt attributes, <button> text content) is insufficient. The first rule of WAI-ARIA is "If you can use a native HTML element, do so instead of using ARIA." Excessive ARIA usage can actually harm accessibility and may alter screen reader behavior in unexpected ways. Web accessibility practical guides provide additional insights.

From a character count perspective, aria-label text is not displayed on screen but is read by screen readers, so keeping it concise and clear is important. Labels that are too long burden users, while labels that are too short lack information. Generally, concise expressions of 2-3 words are recommended.