secondary wall

American  

noun

Botany.

1. the innermost part of a plant cell wall, deposited after the wall has ceased to increase in surface area.

---

Example Sentences

In those cases the trains are a way to get around highway checkpoints, which act as a secondary wall, hindering illegal immigrants’ attempts to get beyond border communities.

From Washington Times

Of this 47 miles is what's called primary wall, and 33 miles is secondary wall that reinforces the initial barrier.

From BBC

As of last week, Homeland Security had built four new miles of wall up along the border and 22 miles of secondary wall set back from the main wall.

From Washington Times

When all that money is spent, it will pay for about 731 miles of new wall: 278 miles will fence in parts of the border never previously barricaded, 371 miles will replace existing but outdated fencing or vehicle barriers, and the rest will go toward a secondary wall set behind the main border wall.

From Washington Times

Of that, 140 miles of primary and 11 miles of secondary wall replaces old or dilapidated wall.

From Fox News