Acetic Acid is 'water free acetic acid'. Acetic acid glacial is concerted (very little or no water) acetic acid. It is called "glacial" because it forms small crystals slightly below room temperature that look like ice.

Acetic Acid Glacial           99.85 per cent min. by wt.
Water                    00.15% maximum.
Colour     10 APHA maximum.
Formic Acid or Methanoic    0.05 % maximum by wt.
Acetaldehyde    0.05 per cent maximum by wt.
Heavy Metals as Pb    Less than 2 ppm
Iodides                  40 ppb maximum
Permanganate    2.00 hrs. minimum
Freezing Point             16.4° C
Specific Gravity            1.049 at 25° C