genshiwakusei
1. protoplanet
Noun
#282791
1. protoplanet
1. asteroid
1. planet
2. dark horse; surprise contender
1. atomic reactor; nuclear reactor
1. atomic energy; nuclear power
1. nucleus; atomic nucleus
1. nuclear power plant; nuclear power generation
2. primary (e.g. primary immunodeficiency syndrome)
1. origin; beginning
2. primeval; primordial
1. atom
1. atomic bomb; A-bomb