Diffusion

How to spell diffusion

9 letters · 3 syllables

How to pronounce diffusion

Say the part in capitals loudest.

What does diffusion mean?

1. nounThe process of spreading something widely or evenly through a space or population.
2. nounThe movement of particles from a region of higher concentration to one of lower concentration until they are evenly distributed.

Diffusion in a sentence

• The rapid diffusion of news online changed how the company managed its reputation.

• The experiment measured the rate of diffusion as the dye spread through the water.

• Historians study the diffusion of printing technology across medieval Europe.

• Oxygen reaches the bloodstream by diffusion across the thin walls of the lungs.

Where does diffusion come from?

Language of origin: Latin

This word traces back to the Latin verb diffundere, which combined the prefix dis- (here in the form dif-, meaning 'apart' or 'in all directions') with fundere, meaning 'to pour'. The literal image is of a liquid being poured out so that it spreads everywhere, and the related noun diffusio described exactly that scattering or spreading. English took the word in during the late 1300s and 1400s, first to describe the wide spreading of light, knowledge, or substances, and later scientists adopted it for the way particles intermingle and even out through a medium. The same fundere root, meaning 'to pour', also gives us 'fuse', 'confuse', 'refund', and 'profuse', which is a useful reminder that the middle of the word is spelled with a double f and a single s. Remembering the 'pour apart' sense helps keep the -fus- spelling and the -sion ending straight.

How the word is built

• dif- (apart, from dis-)
• fus (poured, from Latin fundere 'to pour')
• -ion (noun of action)