All and Across-the-board

All adjective - Not divided or scattered among several areas of interest or concern.

Across-the-board and all are semantically related In some cases you can replace phrase "Across-the-board" with "All", this terms are similar.

Across-the-board adjective - Belonging or relating to the whole.

All and across-the-board are semantically related in broad in scope topic. Sometimes you can use "All" instead an adjective phrase "Across-the-board".