Pink noise and white noise are both random signals containing all frequencies -- you can think of the difference in terms of the two being EQ'ed differently. Let's take two frequency ranges -- 100-200 Hz and 1000-2000 Hz -- for the example.
Pink noise is equal energy per octave, so the 100-200Hz range would have the same total energy as 1000-2000 Hz since both are an octave.
White noise is equal energy per "number of hz", so the 100-200 Hz range would have one-tenth the energy of the 1000-2000 Hz range. In other words, white noise has louder "high notes" and sounds like the treble is turned way up relative to pink noise
From an audio point of view, pink noise is "flat" across the frequency range and makes more sense for us to use as a reference. The main point of interest with white noise is that it "occurs naturally", ie the noise you get from a radio between channels, the noise you get when you point a radio telescope out into space, the thermal noise you get in an electronic circuit etc...
