ser ‧ geant /ˈsɑːdʒ ə nt $ ˈsɑːr-/ BrE AmE noun [countable]
[ Date: 1100-1200 ; Language: Old French ; Origin: sergent 'servant, sergeant' , from Latin servens , present participle of servire ; ⇨ ↑ serve 1 ]
a low rank in the army, air force, police etc, or someone who has this rank