Meaning of name: Arduinna seems to be very straight forward at first. Delamaare gives the first part Arduo as ‘height’ or ‘high’. Olmstead offers up an etymology derived from Ardbenna, “She of the High Peak”. 
In a personal conversation, Steve Gwiríu Mórghnath Hansen (Modern Gaulish developer) suggests that there is no intristic semantic meaning contained in the suffix, and that *Uinna* is an enlargement of the stem for purposes of personification. This would give the name the meaning of the “high thing is female” or “She who is high”, giving us reason to believe She is a mountain goddess. To evidence this, there is a parallel found in the text of Chateaubleau where the adjective ‘ueionna’ is found and interpreted as ‘wanting/desiring’. The full line: “Nemna líiumi bena ueionna in coro bouido”, which is translated as “[oh] Powers I denounce the woman desiring the cattle contract”. ‘Ueionna’ is a verbal adjective that is enlarged with a semantically empty -n- suffix to turn it into a word relating to a person or entity.
In another personal conversation with Tom Schulze (student of linguistics and languages at Georg-August-Universität Göttingen), there is a chance that ‘unna’ might be related to water which would give us the meaning ‘High Water’ for Arduinna. Considering that there are rivers that run in the Ardennes (Her tutelary dominion), it is not far fetched as a possibility.
There is also the attested goddess Ahuardua (Hadrian’s wall) that possibly corroborates with this meaning, as pointed out by our friends Frankisk Allodium. It should be noted that the Frankisk Allodium considers Ahuardua to have been worshipped or at least dedicated to by Cohors Tungrorum. They write ‘The Tungri lived between the Scheldt and the Rhine, north of the Arduenna Silva’ (They note this while stating it is debatable that Cohors Tungrorum were ethnically Tungri). As we have noted, the Arduenna Silva is the tutelary area of Arduinna which points to a possibility of worship by various tribes in the surrounding area.
Function: Miranda Aldhouse-Green proposes a connection to depictions of a woman riding a boar to Arduinna. This is however ultimately speculation, as there are no inscriptions on the statue to determine who dedicated it or if it was dedicated at all to any being.
Another statue was found that had been attributed to ‘Diana’ with the same motif. This leads to a moment in history where St.Walfroy preached to a people of the Ardennes to stop their worship of Diana.
“Then I came to the territory of Trèves and on the mountain where you are now built with my own hands the dwelling you see. I found here an image of Diana which the unbelieving people worshiped as a god. I also built a column on which I stood in my bare feet with great pain. And when the winter had come as usual I was so nipped by the icy cold that the power of the cold often caused my toenails to fall off and frozen moisture hung from my beard like candles. For this country is said to have a very cold winter.” And when I asked him urgently what food or drink he had and how he destroyed the images on the mountain, he said: “My food and drink were a little bread and vegetables and a small quantity of water. And when a multitude began to flock to me from the neighboring villages I preached always that Diana was nothing, that her images and the worship which they thought it well to observe were nothing; and that the songs which they sang at their cups and wild debauches were disgraceful; but it was right to offer the sacrifice of praise to all-powerful God who made heaven and earth. I often prayed that the Lord would deign to hurl down the image and free the people from this error. And the Lord’s mercy turned the rustic mind to listen to my words and to follow the Lord, abandoning their idols. “
According to Bernadette Filotas, there might be clues to beliefs concerning Diana in the Ardennes, bringing up St. Martin de Tours’ use of the plural Dianas, which could indicate the goddess’ name being applied to dryads. She does however note that it could be mistaken that Martin used Diana in the plural. Even though it is tempting to take Diana as a later interpretation of Arduinna, it is far from certain that this is how She was viewed in antiquity.
Iconography: Arguably by Aldhouse-Green, a boar. Mountain. High places.
Attested Sources: At least one inscription in Düren, Germany.
Interpretatio Romana: Arguably Diana.
Senobessus Bolgon interpretation: Arduinna is most assuredly a god of high places, be it forests or mountains. Considering She was the tutelary god of the Ardennes, Her most holy place (a Mecca if you will) would be the aforementioned locale. That being said, since there are a few other areas that have the title Arduenna Silva applied to them besides the ‘Modern’ Ardennes. This stands to reason that She is not just restricted to Her previously designated area of worship.
There is an interesting idea put forth by Heather Campbell (member of The Gaulish Polytheism Community on Facebook) in regards to the boar in the Ardennes however:
“In permaculture, pigs are essential in pasture and crop rotation as they are nature’s roto-tillers. They loosen up and aerate the soil, manicure root systems, exposing pathogens to the sun, uprooting and consuming disease to convert to fertilizer. This action is so healthy before planting. In forests (like the Ardennes) porcine mayhem makes room for new saplings and healthy root systems. Tree communities are much healthier if wild hogs are present (in numbers managed by wolves). There are metaphysical lessons here if one is inclined to symbology.”
Presented with this, Senobessus Bolgon also considers Her also to be a god of the forests, forestry, rivers in these high places as well as a protectress of animals but also of the hunt via her late interpretatio as Diana.
The Silva Arduenna stretched from the Rhine and the borders of the Treveri to the lands of the Nervii and Remi, giving some speculation that this god was important to those tribes.
1. Dictionnaire de la langue gauloise (2nd ed.) by Xavier Delamarre (2003) P. 51
2. Gods of the Celts and Indo Europeans by Garret Olmstead P. 429
4. Gods of the Celts by Miranda Aldhouse-Green p. 180
5. Images des Dieux de la Gaule by Simone Deyts
6. Auf den Spuren der Dea Arduinna: Eine Auswertung der Forschungserkenntnisse zu einer keltischen Lokalgottheit
by Nico Biermanns
9. Pagan Survivals, Superstitions and Popular Cultures in Early Medieval Pastoral Literature by Bernadette Filotas P. 74-75
11. Dictionnaire de la langue gauloise (2nd ed.) by Xavier Delamarre (2003) P. 51-52