IPA: /ˌsʌplɪmɛnˈteɪʃən/
KK: /sʌplɪmɛnˈteɪʃən/
Something that is added to enhance or complete something else.
The doctor recommended supplementation with vitamins to improve my health.
Supplementation → It is formed from "supplement" (from Latin *supplementum*, meaning something added) and the suffix "-ation" (meaning the action or process of). The word "supplementation" refers to the process of adding something to enhance or complete something else.
Think of 'adding something' ('supplement') to improve or complete a whole, which is what 'supplementation' means.