Short answers, pulled from the story.
The name Geri stems from a Proto-Germanic adjective meaning greedy or ravenous. Old Norse texts describe the term as deriving from roots found in Burgundian girs and Old Swedish giri which translate to concepts of greed, desire, or insatiable appetite.
Odin provides food to his wolf companions while consuming only wine himself. Chapter 38 of the Prose Edda book Gylfaginning states that Odin gives all table food to the wolves and uses wine as both meat and drink for the one-eyed god.
The Böksta Runestone displays an image of a rider on horseback flanked by two wolves representing Odin hunting alongside his canine companions. The Sutton Hoo purse-lid features decoration showing a one-eyed figure between two wolves though details are hard to see in photographs.
Historian Michael Spiedel connects Geri and Freki with archaeological finds depicting figures wearing wolf pelts. He believes this points to a pan-Germanic wolf-warrior band cult centered on Odin known as Úlfhéðnar in Norse mythology.
Maurice Bloomfield connected the pair with the two dogs of Yama in Vedic mythology and saw them as a Germanic counterpart to a more general Cerberus theme found across cultures. Jacob Grimm observed a connection between Odin and the Greek Apollo where both wolf and raven are sacred.