"I eat eggs."

Translation: Jag äter ägg.

[muahahahh]

how can I define what's singular and what's plural in case of ägg?

[Iikka]

Singular would have the article ett in front of it.

[G0108]

Think of it like this, you would not say "I eat egg", you would say "I eat an egg", in which case it would be "Jag äter ett ägg"

[ghoti_]

My friend is allergic, but I eat egg.

[BarbaraMorris]

I was thinking of the same example. But in this case, interpreting it as "I eat eggs" would mean the same thing.

[BarbaraMorris]

From context. We have the same issue in English with words like sheep.

[votears]

For those who got confused by the case/number/gender of "egg", ->http://en.wiktionary.org/wiki/%C3%A4gg

[sixelabee]

I eat eggs. Lol

[elsafleur]

So if the noun in plural you do not need an article?

[muahahahh]

all neuter nouns ending in a consonant are unchanged in the plural. (from wiki). so it's only about the neuter nouns.

[HelenCarlsson]

You can of course say for example "jag äter två ägg", "jag äter åtta ägg" or "jag äter många ägg" but simply "jag äter ägg" is correct as well.