Looking back I see that you have mainly posted in the water turtle and box turtle categories, so I feel that your question is for real, and not just something to get attention. So, in that vein, I will answer accordingly.
A tortoise is a typically herbivorous turtle that lives on land.
It sort of is determined by where you live too. In Australia land turtles are referred to as 'turtles,' and water turtles are referred to as 'tortoises.'
But, for our purposes, here on the Forum, a tortoise is a land turtle...not to be confused with your box turtle, that lives on land but is a turtle.
a turtle when it walks drags its shell on the ground. When a tortoise walks he walks on his toes and his shell is up in the air not draging on the grown.