Aqua (from Latin: aqua for water) is a variation of the color cyan which is identical to the color electric cyan, one of the three secondary colors of the HSV color wheel, along with magenta and yellow. It is precisely halfway between green and blue on this color wheel. This color should be distinguished from the primary subtractive color process cyan used in printing, which is a deeper shade of cyan (also known as deep aqua).

In traditional print media, "aqua" is short for aquamarine, a distinct color from aqua. The words "aqua" and "cyan" are used interchangeably in computer graphics, and especially web design, to refer to the additive secondary color "electric cyan." Traditionally that color, defined as #00FFFF in hex, or (0,255,255) in RGB, is called "cyan," but X11 color names introduced the alternative name "aqua." Later, W3C popularized the name by using it in the named color palette of HTML 3.2 specifications.