surroundings

Here the word is plural in form and in grammar, and this sense takes no singular: your surroundings are, never is. It reaches past mere place to circumstances. In Arthur Conan Doyle's The Lost World (1912), a man's manner is unmoved "by any change in his surroundings." Later use stretches it further, to penthouselike rooms and even, in Uché Okonkwo's Luxury Online (2010), to virtual surroundings.

Only the noun can take this -s. The singular surrounding is also the present participle of surround, as in the surrounding hills, but a verb form never pluralizes. So surroundings always points back to the noun, meaning an outlying area or an environment. That environment meaning is the one carried by the plural-only "environment" sense.

Physics draws a sharp line here. The system is whatever is under study, and everything else in the universe counts as its surroundings, near or far. The two exchange energy or matter across the system's boundary, so a gas that expands does work on its surroundings. Unlike the everyday "environment" sense, nothing about this meaning is local.