This is the 860th most frequent Icelandic word.
sýningunni
"The exhibition" or "the show" (definite dative form of "sýning").
In this sentence, 'sýningunni' refers to 'the exhibition,' indicating a specific event that was attended.
Við fórum á sýningunni í gær.
We attended the exhibition yesterday.
Here, 'sýningunni' means 'the exhibition,' describing the location where the painting was shown.
Þetta málverk var sýnt á sýningunni.
This painting was displayed at the exhibition.
In this usage, 'sýningunni' refers to the venue or event where the speaking occurred.