noun

• (nautical) Permission to use a port given to a ship after compliance with quarantine or on conviction that she is free of contagious disease.
  "It is here a cuſtome ſtrictly obſerued (as alſo elſevvhere vvithin the Streights belonging to the Chriſtians) not to ſuffer any to trafficke or come aſhore before they haue a Pratticke from the Signoirs of Health: vvhich vvill not be granted vntill forty dayes after their arriuall, […] Notvvithſtanding, they vpon requeſt vvill carry you to the Lazaretto (vvhich is in the nature of a Peſt-houſe) there to abide vntill the date be expired. But if any fall ſicke amongſt them in the meane ſeaſon, their Pratticke is accordingly prolonged. A great inconuenience to the Merchants, but at Venice intollerable: vvhere vvhen they haue Pratticke, they are enforced to vnlade at the Lazaretto."
• (obsolete) Practice; habits.
  "Whereas in private teaching, their company is either superiors, inferiors, and if equals, but a few, without the liberty and variety of pratique as in a populous school."