A resolution (size) of 960 x 540 pixels. This often refers to the resolution of a display, or it can refer to content, such as the resolution of a photo or video file.
qHD is a common resolution for phone displays (in 2011-2014.)
Higher resolutions offer more pixels and therefore more detail. qHD is higher-resolution than VGA or WVGA.
"Full" HD is 1920 x 1080 pixels. This is the common HD television resolution known as 1080p. qHD is one-quarter the area, hence the name Quarter-HD (qHD).
qHD should not be confused with QHD. Upper-case "Q" means quad (4x), while lower-case "q" means quarter (1/4).