From Biology-Online Dictionary | Biology-Online Dictionary

Disk sensitivity method

a procedure for testing the relative effectiveness of various antibiotics; small disks of paper (or other suitable material) are impregnated with known, appropriate amounts of antibiotic, and then placed on the surface of semisolid medium that has been previously inoculated with the organism being tested; after suitable periods of incubationlack of growth in zones about the various disks indicates the relative effectiveness of the antibiotic.