diffusion, n.
1 the act or an instance of diffusing; the process of being diffused.
2 Physics & Chem. the interpenetration of substances by the natural movement of their particles.
3 Anthropol. the spread of elements of culture etc. to another region or people.

Derivative

diffusionist n.

Etymology

ME f. L diffusio (as DIFFUSE)

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ROGET THESAURUS

diffusion

Dispersion

N nonassemblage, dispersion, dispersion, disjunction, divergence, aspersion, scattering, dissemination, diffusion, dissipation, distribution, apportionment, spread, respersion, circumfusion, interspersion, spargefaction, affusion, waifs and estrays, flotsam and jetsam, disjecta membra waveson, unassembled &c (assemble), dispersed, sparse, dispread, broadcast, sporadic, widespread, epidemic, adrift, stray, disheveled, streaming, sparsim, here and there, passim.

Presence

N presence, occupancy, occupation, attendance, whereness, permeation, pervasion, diffusion, ubiety, ubiquity, ubiquitariness, omnipresence, bystander, present, occupying, inhabiting, moored, resiant, resident, residentiary, domiciled, ubiquitous, ubiquitary, omnipresent, universally present, peopled, populous, full of people, inhabited, here, there, where, everywhere, aboard, on board, at home, afield, here there and everywhere, in presence of, before, under the eyes of, under the nose of, in the face of, in propria persona, on the spot, in person, in the flesh, nusquam est qui ubique est.

Rarity

N rarity, tenuity, absence of solidity, subtility, subtilty, subtlety, sponginess, compressibility, rarefaction, expansion, dilatation, inflation, subtilization, vaporization, evaporation, diffusion, gassification, ether, rare, subtile, thin, fine, tenuous, compressible, flimsy, slight, light, cavernous, spongy, rarefied, unsubstantial, uncompact, incompressed, rarefiable.

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