What do the terms porosity, permeability, and texture mean?

Texture, porosity, and permeability are physical properties of soil.

Texture:

Soil is a mixture of three separates. A separate is a category of soil based on grain size. The three separates in soil are: sands, silts, and clays. Sands have the coarsest grains and clays have the finest grains. The texture of soil is determined by the relative amount (percent) of each separate present in the soil.

Porosity is the amount of space between soil particles. The spaces between the particles are called void spaces. The amount of space between soil particles is determined by the shape and arrangement of the soil particles themselves. The porosity of a soil can be quantified by dividing the volume of the pore space (void space) by the volume of the total soil sample.

Permeability is an indication of how well soil can transmit a fluid such as water. Permeability is influenced by the size and arrangement of the spaces between the soil particles.