Hi Bertha,
Here's an explanation of what a 2x4 is (two by four)so this should help you.
I don't know about the TM and I'm not sure if it is referring to trademark here. Do you have any more references to TM?
Explanation
A wooden beam with a cross-section of roughly 2"x4". It's the most
common size wooden beam used in construction. The walls of all homes
build in America during the last 50 years are framed using
two-by-fours.

At one point in time, two-by-fours used to have a cross-section of
exactly 2"x4". For reasons that I forget, the actual size of a
two-by-four is a bit less than 2" by a bit less than 4". Maybe it had
something to do with making these wooden beams have nicer, rounder
measures when converted to metric. Or, it may be that the lumber
industry started making two-by-fours smaller to save on wood during
some shortage or other, and the size change stuck. Either way, we
still call them two-by-fours.

You'll also find 2-by-2's, 2-by-6's, 4-by-4's (for heavier-duty
posts), 1-by-8's, and 1-by-2's. These are the most common sized
wooden beams used in construction in America these days.
[email protected]/msg00370.html" rel="nofollow noopener" target="_blank">http://www.mail-archive.com/[email protected]/msg00370....

Viga de madera??