frenum
noun
fre·num ˈfrē-nəm 
plural frenums or frena ˈfrē-nə
: frenulum sense 1
Word History
Etymology
New Latin, from Latin, bridle, reins, and bit; probably akin to Latin frendere to grind — more at grind
First Known Use
1741, in the meaning defined above
Medical Definition
frenum
noun
fre·num ˈfrē-nəm
plural frenums or frena -nə
: frenulum