plural of blue-print

(dated) Alternative spelling of blueprint

A bright, metallic blue colour.

A blue pigment, Prussian blue. / The rich blue colour of this pigment.

plural of boy in blue

A diluted blue hair dye used to reduce the yellowed or translucent appearance of greying hair on older women (because the ability to see the colour blue decreases with age).

A signal or process with a frequency spectrum such that the spectral energy density is proportional to the frequency.

the planet Earth

plural of blue film

(Internet) A hyperlink displayed in blue, traditionally indicating that the user has not yet followed the link.