n.
Pronunciation: ˌ pla-n ə - ' tä-l ə -j ē
Function: noun
Inflected Form: plural -gies
Date: 1907
: a branch of astronomy that deals with the condensed matter of the solar system and especially with the planets and their moons
– plan · et · o · log · i · cal \ ˌ pla-n ə -t ə - ' lä-ji-k ə l \ adjective
– plan · et · ol · o · gist \ ˌ pla-n ə - ' tä-l ə -jist \ noun