What does rarefying mean?
Rarefying means making something less dense, less concentrated, or less common. In scientific and technical contexts, it usually describes reducing the pressure or density of a gas or other substance, as when air is made less dense in an expanding container. The word can also be used figuratively for effects that reduce concentration, intensity, or prevalence, such as a process that is rarefying attention or weakening the influence of a particular factor. Because it is more specialized and literary than the simpler terms thinning or diluting, rarefying often lends a formal or technical tone. It is the present participle of rarefy and is closely related to rarefaction, the noun for the process of becoming less dense.
To make a substance less dense or less concentrated, especially by reducing its pressure or increasing its volume.
"The apparatus rarefies the air in the tube before the measurement begins."
Chiefly technical in its physical sense, though it can be used figuratively.
Causing something to become less dense, less concentrated, less common, or less intense.
"The rarefying effect of the new technology was felt throughout the industry."
Usually used attributively in formal or technical writing.
Rarefying takes the idea of being rare literally: it describes thinning a substance until it becomes less dense, just as a balloon's air becomes less concentrated as it expands.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does rarefying come from?
The word comes through French from Latin rarefacere, a compound of rarus, meaning rare or sparse, and facere, meaning to make. Its English development followed the model of rarefy, meaning to make rare or less dense. Related English words include rare, rarity, and rarefaction, which all reflect the same Latin root.
Related word forms
How rarefying is actually used
Rarefying is formal and relatively uncommon in everyday speech; rarefy is more usual as the base form. As an attributive participle, it appears especially in technical and figurative expressions such as 'rarefying effect' and 'rarefying influence'.
Easily confused with rarefying
Rarefying means making something less dense or less concentrated, whereas ratifying means formally confirming or approving something.