Synonyms for marrow

the fatty network of connective tissue that fills the cavities of bones (noun)

any of various squash plants grown for their elongated fruit with smooth dark green skin and whitish flesh (noun)

the choicest or most essential or most vital part of some idea or experience (noun)

• kernel
• substance
• core
• center
• centre
• essence
• gist
• heart
• inwardness
• meat
• nub
• pith
• sum
• nitty-gritty