navel-string
/ˈneɪvl strɪŋ/noun
The umbilical cord. In later use frequently in to bury one's navel-string and variants (originally and chiefly Caribbean ): to feel a strong bond of loyalty or attachment (to a particular place or institution).
Origin
Late 16th century; earliest use found in Philip Sidney (1554–1586), author and courtier. From navel + string.