"σίγμα"

Translation: sigma

[pavlin.petrov]

If I just input 'Σ' or 'σ' instead of 'σίγμα', it will complain that I write it in English, not in Greek.

[mkTDuX]

Why is the letter alone sometimes correct and sometimes not?

[G.Georgopoulos]

In case you encountered this in a listening exercise, please note that only the displayed (main) translation is considered correct when it comes to listening exercises.

[BarryKinna]

Yea same here