Dimensionless

Part of speech: adjective

Definitions

1. Having no physical units of measurement; a quantity or ratio where all units cancel out to leave only a number
2. Lacking any associated physical dimensions, a concept or value that is purely numerical without measurement
3. a characteristic that does not depend on traditional spatial or temporal scales, resulting solely in a ratio or numerical expression

Etymology: Dimensionless is a plain compound with no dramatic backstory: "dimension" joined to the suffix "-less", meaning "without". The suffix descends from an Old English word for "lacking" that survived as an ending, so "dimensionless" literally means "without dimension." The base word carries the older history. "Dimension" comes from Latin "dimensio", a measuring out, formed from "dis-" (apart, in different directions) and "metiri" (to measure). Its sense of spatial extent came into English later, and it is the measuring-apart idea that makes the compound work: a dimensionless quantity is one that has been measured and found to be a bare number, with no length, mass or time attached.

Synonyms: unitless, non-dimensional, abstract, indeterminate, unquantified

Antonyms: dimensional, quantifiable, measurable, tangible, defined