lan ‧ cet /ˈlɑːnsət, ˈlɑːnsɪt $ ˈlæn-/ BrE AmE noun [countable]
[ Date: 1400-1500 ; Language: French ; Origin: lancette , from lance ; ⇨ ↑ lance 1 ]
1 . a small very sharp pointed knife with two cutting edges, used by doctors to cut skin and flesh SYN scalpel
2 . lancet window/arch technical a tall narrow window or ↑ arch that is pointed at the top