This is the 11259th most frequent Russian word.
двухметровой
"Two-meter-tall" or "two-meter-long."
In this sentence, 'двухметровой' is used as an adjective describing the wall. It indicates the height of the wall as being two meters.
Он стоял рядом с двухметровой стеной.
He was standing next to a two-meter wall.
Here, 'двухметровой' qualifies the word 'доска' and refers to the extension or length of the board, denoting it as two meters.
Мы купили доску длиной двухметровой.
We bought a board that is two meters long.
In this example, 'двухметровой' modifies 'ветка' to indicate the physical dimension of the branch, specifically its length of two meters.