Vocabulary What does 骨子 (こっし, kosshi) mean? 骨子 (こっし, kosshi) means main point; gist; essentials. Quick factsReadingこっしRomajikosshiPart of speechnoun 骨子こっしkosshimain point; gist; essentials1noun main point; gist; essentialsKanji in this word骨bone子child