radiation

noun radiations

1. countable, uncountable The shooting forth of anything from a point or surface, like diverging rays of light. The radiation of love from the crowd was addictive to the young singer-songwriters.
2. abbreviation, countable, ellipsis, often, uncountable Ellipsis of electromagnetic radiation.electromagnetic radiation heat radiation
3. countable, uncountable The process of radiating waves or particles.
4. countable, uncountable The transfer of energy via radiation.
5. countable, uncountable Radioactive energy. It's Christmas at ground zero / And if the radiation level's OK / I'll go out with you / To see all the new / Mutations on New Year's Day
6. countable A rapid diversification of an ancestral species into many new forms. So the question is: have plants and animals retained over this huge amount of time—whole radiations of mammals have come and gone in this period—have they retained these potentially costly characteristics?