Observables

Part of speech: noun

Definitions

1. Representing physical quantities or phenomena that can be measured or quantified in experiments or observations
2. Relating to variables that are directly perceivable and can be used to confirm theories in scientific research
3. Denoting attributes or parameters that can be detected and recorded through sensory experience or instrumentation

Etymology: "Observables" is the plural of "observable", an adjective-turned-noun that scientists use for things that can be directly perceived and therefore checked against a theory. The base word "observe" came into English from Latin "observare", meaning to watch, keep, or attend to, built from "ob" (toward) and "servare" (to keep watch over). The suffix "-able" arrived through Old French from Latin "-abilis", and it means capable of being acted upon, so an observable thing is one that can be watched or noticed. The noun use is the interesting step. The adjective "observable" described anything that could be seen or noticed, but in scientific writing it became a noun for the measurable quantities a theory predicts. The word thus moved from describing a quality to naming the things that carry that quality.

Synonyms: variables, data, measurables