1. in a manner that releases heat energy to the surroundings; in an exothermic way
Usage: chemistry and physics term; describes how a chemical reaction or process occurs

Examples

• The combustion reaction proceeds exothermally, warming the surrounding air.
• When sodium reacts with water, it reacts exothermally and produces hydrogen gas.
• The neutralization of an acid and base occurs exothermally.
• Rusting happens exothermally, though the heat released is usually too small to notice.
• The explosion was exothermally driven by the rapid decomposition of the compound.