精髓

jīngsuǐ
marrow; pith; quintessence; essence

CEDICT

Entry Composition

1 精 jīng
  1. essence
  2. extract
  3. vitality
  4. energy
  5. semen
  6. sperm
  7. mythical goblin spirit
  8. highly perfected
  9. elite
  10. the pick of sth
  11. proficient (refined ability)
  12. extremely (fine)
  13. selected rice (archaic)
2 髓 suǐ
  1. (bound form) bone marrow; (fig.) innermost part
  2. (botany) pith