fontanelle

noun

Etymology: Borrowed from French fontanelle, from Old French fontenelle, a diminutive of fontaine (“fountain, spring”) + -elle, from Late Latin fontāna, from Latin fontānus, from font- + -ānus. By surface analysis, font + -an + -elle.

1. A soft membraneous spot on the head of a baby due to incomplete fusion of the cranial bones.
2. A structural component of some woodwind instruments, such as recorders and shawms, resembling a barrel with holes bored into it, designed to protect the keywork and to allow the sound to project.