Pinking shears are scissors whose blades are sawtooth instead of straight. Pinking shears will leave a zigzag pattern instead of a straight edge. These scissors can be used for decorative cuts and there are a number of patterns (arches, sawtooth of different aspect ratios, or asymmetric teeth).
Pinking shears also have a utilitarian function for cutting woven cloth.
Cloth edges that are unfinished will easily fray (the weave becomes undone and threads pull out easily). The sawtooth pattern doesn't prevent the fraying but limits the length of the frayed thread and thus limits the damage.
The cut produced by pinking shears has given its name to pinks; hardy carnations of the Dianthus genus named for their petals' "pinked" edges. The color pink was then named after these flowers.
