Mascara is a cosmetic

Cosmetics

Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...

 commonly used to enhance the eyes. It may darken, thicken, lengthen, and/or define the eyelashes. Normally in one of three forms—liquid, cake, or cream—the modern mascara product has various formulas; however, all contain the same basic components of pigments, oils, waxes, and preservatives.
The Collins English Dictionary

Collins English Dictionary

The Collins English Dictionary is an important printed dictionary of English. It is published by HarperCollins.The first edition of the Collins English Dictionary with Patrick Hanks as editor and Lawrence Urdang as editorial director, was a milestone in British dictionary making as it was the...

defines mascara as "a cosmetic substance for darkening, coloring, and thickening the eyelashes, applied with a brush or rod." The Oxford English Dictionary

Oxford English Dictionary

The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

(OED) adds that mascara is occasionally used on the eyebrows as well.

The OED also references mascaro from works published in the late 1800s.