Water content in a bulk material. In English, a distinction is made between moisture (in material) and  humidity (in the air). The terms moisture and humidity generally only refer to water content and other liquids are not included in this definition.

However, in everyday practice, it is difficult to identify and determine just the water content when other liquids are present. This means that measurement results include proportions of other liquids, whereby the influence of the ph-value is significant.

The overall water content of a damp substance is made up of the free water, the surface moisture, the inner moisture (hygroscopically bound water) and the water of crystallization

Further references:
Degree of moistening
Moisture measurement
Humidity sensor
Sand moisture