Gryffindor could be derived from griffin, griffin in English, a mythological creature with lion's body and eagle's head.
In Anglo-Saxon or Old High German pain means door.
In French d'or it means of gold, one of the colors of the Gryffindor House, although it is also related to the Greek word dora meaning gift.
In French griffe means claw that has relation with the claws of the lion.
Gryffindor can be explained very well by heraldry: "Gryffin" can mean the beast "griffin" and "pain" can refer to the metal of gold enamel.