When the term material is used in the plural, that is, materials, it is generally referring to the set of elements that are necessary for specific activities or tasks. The notion of materials can be applied to different situations and spaces, but it will always revolve around several elements that are important and useful to carry out a certain action, as well as being objects that must be used together.
A characteristic case of the idea of materials is when it comes to those elements that are used in construction. For example, bricks, tools of various kinds, paint, plaster, electrical elements, beams, metals, wood and others are often considered materials. All of them together are necessary to build or repair certain spaces and are always the basic elements that must be counted on. In this sense, machinery can enter into the concept of materials, but this will be more about the raw material to be used.
The term materials is also applied to those elements that have to do with school activities. Materials such as pencils, pens, paper, glue, colors, erasers, folders and markers are some of the most basic elements that a student must have in order to develop school assignments in the best possible way.
Of course, the notion of 'materials' can be applied to many other situations, and in some cases become a set of abstract elements, no longer concrete. An example of this is when we talk about pedagogical materials (which can be ideas rather than objects), social materials (modes of behavior and attitude), psychological materials (elements that make up the personality of an individual), etc. These materials, however, share the notion of variety and relevance for the specific situation with those materials considered concrete, such as those mentioned above.