Nouns which refer to things we can count are countable.
The plural of a countable noun is formed by adding the ending –(e)s:
Stamp-stamps, temperature- temperatures, idea- ideas, refugee-refugees, church-churches
If the noun ends in a –y with a consonant in front, the -y is turned into -ie in the plural:
Country-countries, territory-territories. But: day- days
These nouns with an -o at the end have –es in the plural: cargo-cargoes, domino-dominoes, echo-echoes, embargo-embargoes, hero-heroes, potato-potatoes, tomato-tomatoes, torpedo-torpedoes, veto-vetoes.