: the quality or state of being expanded. : the increase in volume of working fluid (such as steam) in an engine cylinder after cutoff or in an internal combustion engine after explosion. The book …

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.

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 …

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.

the state or quality of being expanded:[uncountable] Future expansion of the business will require us to build more factories. The runway is undergoing expansion to allow bigger planes to land …

Definition of expansion noun in Oxford Advanced American Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Oct 31, 2025 · (building) A new addition. synonym Synonym: annex My new office is in the expansion behind the main building.

EXPANSION meaning: 1 : the act of becoming bigger or of making something bigger the act of expanding; 2 : a more complete and detailed written work or set of comments based on …

Definition of expansion. English dictionary and integrated thesaurus for learners, writers, teachers, and students with advanced, intermediate, and beginner levels.