Definition of decaffeinate in English:
 decaffeinate
verb diːˈkafɪneɪtdiˈkæfəˌneɪt
[with object]Remove most or all of the caffeine from (coffee or tea)
 there are different ways to decaffeinate coffee
Derivatives
  
noundiːˌkafɪˈneɪʃ(ə)n
 I do not enjoy the decaffeinated version of green tea and have been told that the decaffeination process introduces chemicals into the tea.
 Example sentencesExamples
-  But instead, we're going to do a little experiment in decaffeination.
 -  Eve replies: Total decaffeination is not an option.
 -  One hypothesis is that when these women were drinking coffee when they, were younger, the decaffeination process involved chemical solvents that have been implicated in connective-tissue diseases [like rheumatoid arthritis].
 -  Big companies had been frightened by the ‘hysteria ‘in Europe over GM foods, and they had already invested huge sums in industrial decaffeination plants.’
 
   Definition of decaffeinate in US English:
 decaffeinate
verbdēˈkafəˌnātdiˈkæfəˌneɪt
[with object]Remove most or all of the caffeine from (coffee or tea)
 there are different ways to decaffeinate coffee