Another possibility is that it is a composite name the first part of which (Sin-gi) means "Old prayer" ("sean guí" in modern Irish), implying that this was originally a site of Celtic religious significance, in addition to becoming a fortress (dun). This would also fit in with the ancient Celtic burial practice remnants there. However, etymologically speaking this is extremely unlikely. The Modern Irish form is actually "sean-ghuí", and is from Old Irish "sen-guidi", "guidi" being from the Common Celtic stem "guedyo-" "beg, implore, pray". Given the age of the name "Singidunum", the expected form would be something like *senogwedyodunom, Latinised as "*Senoguediodunum".