An "applicator brush" is a small brush or tool used to distribute or apply a substance, such as paint, makeup, or adhesive, onto a surface in a controlled and precise manner. Full definition
I love that this pink clay mask comes with a cute little applicator brush, because I've been known to get my hands all messy when I apply a mask. (glassofglam.com)
The thin applicator brush helps you achieve a precise and professional finish. (stylecraze.com)
A Little Cosmetics essential set includes everything children will desire in a play - based makeup set, such as a powder compact with mirror and puff, lip glosses with a rolling applicator, eyeshadows, trendy glitter pots, blush, and a variety of applicator brushes that fit inside a sweet, yet trendy zippered pouch. (thespruce.com)