An expanding shell of material created by the ejection of the outer layers of a star that explodes as a supernova.
1950s; earliest use found in Fred Hoyle (1915–2001), astronomer.
英汉双解词典包含464360条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。