The British spelling of the process of removing color or reducing colorfulness.
From decolourise + -ation. British English combines the -our- spelling of colour with -ise verb form and -ation noun suffix in a single word.
This is one of English's longest color-related words, and it represents British spelling conventions perfectly—notice how it keeps the 'u' from 'colour' even in this extended technical term, maintaining consistency across the language family!
Complete word intelligence in one call. Free tier — 50 lookups/day.