caffeine

Definitions

General English

Agriculture

  • noun an alkaloid present in coffee, tea and kola nuts, which gives them their stimulating properties

Food

  • The alkaloid found in tea (2–4 per cent by weight) and coffee (1–2 per cent by weight) and in cola drinks, responsible for some of their stimulating properties
http://www.dictionarycentral.com/definition/caffeine.html