The word "woodstain" means different things to different people. A quick explanation:

Wood dye: is mainly colour. Some have a low level of binder in them. They should be use only on bare wood, so they can soak in, and must be topcoated with a stronger, normally clear finish. Some can be combined with a compatible varnish to make a coloured varnish and they can also be combined with woodstains. This helps enormously when you are trying to match in new wood.

Coloured varnish: a colour combined with lots of binder or resin. A varnish sits on the surface of wood, rather than sinking in and is quite high-build offering a protective barrier of see-through colour.

Woodstain: is half-way between a dye and a varnish in terms of use. Generally a satin finish with a good amount of colour and yet a good degree of protection. The high-performance exterior systems tend to have a runny, penetrating basecoat and then a more viscous, higher-build protective topcoat. Most can go on top of bare or treated wood. They are most often micro-porous/breathable.

Colour

Dulux Trade Wood Finishes

Sadolin Classic and Sadolin Extra

Sikkens