Cherenkov Telescope Array (CTA)
this term is not directly explained in the crianca or tecnico summaries; however, it's a space telescope designed to detect very high-energy gamma-rays. The actual explanation and analogy would depend on placing this topic into context as it relates to the topic of detecting 100 TeV gamma-rays, but this particular text doesn't provide much more information.
Technical definition
a ground-based array of telescopes designed to detect very high-energy gamma-rays, with a 50 h observation capability to detect 100 TeV gamma-rays out to ~ 4 Mpc (reduced to 3 Mpc with specific assumptions).