Difference between 水果 and 果实 HSK 5 translates 果实 as 'fruit'. I always refer to fruit as 水果 and so would like to know the difference between 果实 and 水果. My teacher has told me that 水果 is a 果实 but not all 果实 are 水果. Fruits that consist of water should be referred to as 水果 or either 果实, but fruits that do not consist of water should be only referred to as 果实. However, all fruits consist water right? 

Main question: what is the difference between 果实 and 水果
「果實」matches the botanical definition of fruit, and「水果」refers to the colloquial usage. The Wikipedia article sums it up nicely:


  In common language usage (水果), "fruit" normally means the fleshy seed-associated structures of a plant that are sweet or sour, and edible in the raw state, such as apples, bananas, grapes, lemons, oranges, and strawberries. On the other hand, in botanical usage (果實), "fruit" includes many structures that are not commonly called "fruits", such as bean pods, corn kernels, tomatoes, and wheat grains.