Ballot countable or uncountable noun

[Jignesh]

Jigneshbharati:
2 : a process that allows people to vote in secret so that other people cannot see their votes

[count]
They cast their votes in a secret ballot.
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[noncount]
She was elected by secret ballot.

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Please someone explain to me how to recognise or identify uncountable nouns from countable nouns (Without checking a dictionary) I was reading new about the( should I use the here?)US elections and the noun ballot could be used both as a countable and uncountable noun as per the dictionary definitions (learners dictionary). Thanks Jignesh

[Alan]

The noun 'ballot' itself is countable, but 'by secret ballot' is a fixed phrase.

I'm afraid that a good dictionary is your only guide!