The meaning of EXPANSION is expanse. How to use expansion in a sentence.

Expansion is usually due to heating. When substances are heated, the molecular bonds between their particles are weakened, and the particles move faster, causing the substance to expand.

EXPANSION definition: 1. the increase of something in size, number, or importance: 2. the increase of something in size…. Learn more.

1. the act or process of expanding. 2. the state or quality of being expanded. 3. the amount or degree of expanding. 4. an expanded portion or form of a thing.

Mar 20, 2026 · expansion (countable and uncountable, plural expansions) The expansion of metals and plastics in response to heat is well understood. Look up the expansion of 1018 steel at stick welding …

The runway is undergoing expansion to allow bigger planes to land there. [countable] an expanded portion or form of a thing: The book is an expansion of a series of articles.

Expansion is the part of an engine cycle in which the fluid increases in volume and makes a part such as a piston or flywheel move. The expansion of the gas pushes the piston inside the cylinder. The …

The act or process of expanding. The expansion of metals and plastics in response to heat is well understood.

There are 14 meanings listed in OED's entry for the noun expansion, two of which are labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation evidence.

The league is undergoing expansion. This book is an expansion of a lecture series. Her remarks today were an expansion on her earlier comments regarding the budget.