A silicone sealant is a sticky substance made of silicone that is used to seal cracks or gaps in things like windows, sinks, or showers. It helps to prevent leaks and keep things watertight. Full definition
Two tubes of gray silicone sealant were thrown against an office building at 101 N. Arlington Heights Road between June 15 at 8 p.m. and June 16 at 8 a.m. (articles.chicagotribune.com)
Of course, there are sometimes tradeoffs; my car recently failed its smog check because the intake manifold warped from the heat, and rather than spend a thousand dollars buying a new manifold that might simply warp again, I had it fixed with high - temperature silicone sealant instead. (mechanics.stackexchange.com)