Hardwoods or hard timbers are generally more durable and dense then softwoods or soft timbers although not all are harder than softwoods the main differences between them are botanical. You are able to identify hard timber trees by characteristics such as their leaves because these types of trees have broader leaves than soft timber trees.
Just like hardwood, softwoods or soft timbers are not necessarily soft or less dense it is just more likely that they are softer than hardwoods. The visual differences in soft timbers compared with hard timbers include things such as usually being lighter in color and usually softer. Soft timbers come from trees that are conifers meaning that their leaves are usually needle shaped instead of broad like a hard timber trees leaves.
Medium density fiber board is made basically the same way as particle board which is by gluing the fibers together with a resin and then compressing the board under heat, later the board is cut into appropriate lengths after it has dried. The resin used in this fiber board is toxic and because the fibers are so fine they are easy to breathe in so the timber should be cut in a well ventilated area or somewhere with a dust collection system.
Particle board is a manufactured board that is often used in furniture because it can be made cheaply and is more affordable than solid timber but has a similar look.
It is mostly found in furniture that require large pieces such as table tops, desks and TV cabinets, this saves people from having to bond two pieces of timber together to achieve the same size. Veneer is very thin timber that is cut 3 millimeters or less and used to cover either particle board or MDF to give the surface a wood grain appearance.
Strips of this wood are also used to make plywood as it is glued in layers to make it light weight and strong. This product is widely used in woodwork because it is a useful product that is used to make cheaper furniture like particle board look more like high quality furniture.