protoplanetary nebula (English, noun)
expansion: protoplanetary nebula (plural protoplanetary nebulae or protoplanetary nebulas)
Senses:
topics: astronomy
natural-sciences
glosses: A stage in stellar evolution when a star starts to shed its outer layers before coming a true planetary nebula.
Forms:
form: protoplanetary nebulae
tags: plural
form: protoplanetary nebulas
tags: plural