Paywall
A paywall is a method of restricting access to content via a paid subscription. Beginning in the mid-2010s, newspapers started implementing paywalls on their websites as a way to increase revenue after years of decline in paid print readership and advertising revenue. In academics, research papers are often subject to a paywall and are available via academic libraries that subscribe.
GeoWall
This article uses the word 'GeoWall' as a convenient trisyllabic equivalent for "low-cost polarization-based dual-projector interactive 3D stereoscopic system". Interactivity is a crucial aspect to GeoWalls, particularly for real-time data exploration. Without interactivity, a GeoWall is merely a system for viewing 3D films — a cheap 3D IMAX on a smaller screen.