IPA: /ˈdɛkəˌliːtə/
KK: /ˈdɛkəˌlitər/
A unit of measurement for volume in the metric system, equal to ten liters.
The recipe calls for a decaliter of water to make the soup.
Decaliter is formed from "deca-" (meaning ten) and "liter" (from Latin "litera", meaning letter or unit of measurement). The word refers to a metric unit that is equal to ten liters.
Think of 'deca-' meaning ten, and 'liter' as a unit of measurement — so a decaliter is simply ten liters.