The word "Eucharist" means "Thanksgiving".  The word Mass is a short hand way of describing the Eucharist. Sometime the word Eucharist is used to mean "Holy Communion" .  

Eucharist = Thanksgiving. In celebrating the Eucharist, the Mass, we give thanks to God for all the blessings we have received, especially for, being able to experience the life that Jesus Christ has invited us to share (unity, peace and love) and how to share that life with others today.