The amount of moisture in a food is described as available water and is expressed as

This is expressed as Moisture Content or Water Content

Most food items have a water content. Even seemingly 'solidified' foods such as a piece of bread or bun have a certain water content in them.

For vegetables and fruits, the water content as a percentage of the weight can be huge.

For example, fruits such as Watermelons contain 92% in every bite with just 6% sugar and 2% fiber by weight.