What does 'Hue' mean in Oil Colour paints?

The term "hue" is generally used to indicate when a traditional colour such as cadmium red or cerulean blue is matched for hue by use of other pigments. Sometimes this would mean non toxic pigments are used to replace others which are considered more harmful. Hue colours are not weaker or sub-standard, which some artists wonder about because of the significant price difference. Another thing to note is that although matched as near as possible, the "hue" may not behave in the same way, particularly when mixed. Mixtures of hues will often give brighter colours than their genuine counterparts. In recent years the term hue has appeared in artists ranges following the introduction of the ASTM standard in the USA which requires colours not made from the named pigment to carry the description hue together with the names of the colours used. For example” Flake White Hue: titanium dioxide/zinc oxide”. Unfortunately not all colour manufacturers follow this practice.