means A cat with a coat of stripes, swirls, or spots — typically marked with the telltale 'M' on the forehead; also, by extension, the patterned silk fabric the look is named after.

from From the French 'tabis,' a kind of striped or watered silk, which traces back through medieval Latin and Italian to the Arabic 'attabiya' — a quarter of Baghdad named for a prince, where this striped taffeta was famously made. The fabric's rippling pattern reminded people of a streaked cat's coat, and so the silk lent its name to the animal. (The use of 'Tabby' as a generic name for a female cat came later, helped along by the personal name.)