This is the 437th most frequent Estonian word.
riikide
"Riikide" means "of countries" in English.
Here, 'riikide' is in the plural genitive case, indicating possession or association, relating to the economies of the countries.
Riikide majandused varieeruvad suuresti sõltuvalt nende ressurssidest.
The economies of countries vary greatly depending on their resources.
The word 'riikidest' is in the plural ablative case form, representing countries from which or among which something is done.
ÜRO on rahvusvaheline organisatsioon, mis koosneb paljudest riikidest.
The UN is an international organization composed of many countries.
In this sentence, 'riikide' illustrates the genitive case in a context of relation or connection, specifically between the countries.