What does decolour mean?
To decolour is to deprive a substance of its colour — to bleach it, whether by chemical treatment, filtration, or prolonged exposure to light and air. The verb appears most often in technical and industrial settings: chemists decolour solutions using activated carbon, textile workers decolour fabrics before re-dyeing them, and manufacturers decolour oils and syrups to achieve a pure, pale product. It can also describe gradual, natural loss of colour, as when sunlight bleaches a curtain or age pales a photograph. The word carries a precise, somewhat formal tone; in casual conversation most speakers would simply say 'bleach' or 'fade'. Spelled 'decolour' in British English and 'decolor' in American English, it derives from the prefix 'de-' (meaning removal) combined with 'colour', from the Latin 'color'. Its noun forms include decolourisation and, less commonly, decolouration.
verbTo remove the colour from something; to bleach or cause to lose its natural or added colouring.
- To remove colour from a substance, especially by chemical treatment such as bleaching.
- To become pale or colourless through natural processes such as light exposure or ageing.
"Prolonged exposure to sunlight gradually decoloured the once-vivid curtains."
"Activated charcoal is used to decolour crude sugar syrup before crystallisation."
"Decades of harsh weather had decoloured the painted shutters to a ghostly grey."
The same word that British chemists write as 'decolour', American labs spell 'decolor' — one of those transatlantic spelling splits that even bleaches its own vowels.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of decolour
'Decolour' combines the Latin-derived prefix 'de-', indicating removal or reversal, with 'colour', which entered Middle English from Old French 'colour', itself from Latin 'color' meaning hue or complexion. The verb arose in scientific and technical English, likely in the 18th or 19th century, as chemistry developed precise vocabulary for bleaching and purification processes. It shares its root with words such as 'colorant', 'coloration', and 'discolour'.
Related word forms
How decolour is actually used
Chiefly used in technical, chemical, and industrial contexts; in everyday speech 'bleach' or 'fade' is more common. The spelling 'decolour' follows British conventions, while American English typically uses 'decolor' or prefers 'decolorize'.
Easily confused with decolour
'Discolour' means to change or spoil a colour (often staining or yellowing), while 'decolour' means to strip colour out entirely.