no, you'd call it a 5 by 10 by 200 piece of wood. Having '2 by four' as a common term is an american thing. Over here you just talk about the size of the wood. in any case you'd call it a 5-by-10. Wood from the store isn't properly dimensioned anyway, and the metric system has this neat thing where it goes in steps of 10 (mostly) so you can pick a unit that's scaled usefully.