A hand-held surgical tool that cuts tissue with a fine beam, standard in Federation medicine for more than a century and occasionally pressed into service for less medical purposes.
The laser scalpel is the basic cutting instrument of Starfleet surgeons, making precise incisions without a blade. By the later 24th century it is being supplemented by newer tools such as the exoscalpel.
In The Next Generation episode The Host, Beverly Crusher uses one in the operations that move the Trill symbiont Odan from his dying host into William Riker.
Others find different uses for it. On Deep Space Nine, Quark cuts open a locked container holding Odo in Invasive Procedures, and Julian Bashir fends off a transformed Odo with one in The Alternate. In the Voyager episode Imperfection, Kathryn Janeway uses a laser scalpel to remove a cortical node from a dead Borg drone and then to face down hostile salvagers.