- an expanding or being expanded; enlargement; dilation
- an expanded thing or part
- the amount, degree, or extent of expansion
- a development or full treatment, as of a topic
- the process or result of working out or giving the full form of a contraction, equation, etc.
- Mech. the expanding in volume of steam in the cylinder of a steam engine after cutoff, or of gas in the cylinder of an internal-combustion engine after explosion
- Sports the act or an instance of increasing the number of teams in a league
Origin of expansionLate Latin expansio from Classical Latin expansus: see expanse