The pictograms in the "AHIRU" logo mean, in order, "stop" (wa), "peace" (ru), and "bird" (tori). However, when you pronounce it you hear "waru tori" - "evil bird". Or, in another context, "rotten poultry". So, the whole thing translates to "Rotten, evil bird who brings an end to peace" - a fitting name for Negaduck.
"Ahiru" is Japanese for "duck".