Hi all

I am looking for words and picture in the internet - but I lack the
right words - in English, Estonian, Danish for the most.

Planks, which can be joined by a tongue, and a groove in the other
side - this must have a name. Usually some 7-10 cm / 3-4 inch. wide,
when connecting they usually leave a small gap, but doesnt have too.

They are used for walls, as well - at least in Denmark - for rear
walls in furniture, most probably because they are easy to use, cheap,
decorative because of the gap.
One example is he http://ecmoebler.mono.net/upl/9321/Reol0_0.jpg

What are the words I am looking for, so I can find drawings on the
net, and maybe something on Wikipedia (it is good for easy
translation).
Just a good picture for a profile drawing would be good.

WBR
Sonnich