A gathered frock for kids with a square neckline and sleeveless design, made of cotton satin cloth in white and light green, sounds absolutely delightful! Here's a detailed description of such a frock:

Color Scheme: The frock could feature a refreshing combination of white and light green. White can dominate the main body of the frock, while light green accents or detailing could be incorporated for a pop of color. This color palette exudes a sense of freshness and vitality.

Fabric: Cotton satin cloth would provide a soft and luxurious feel, making it comfortable for kids to wear. It offers a smooth texture and a subtle sheen, adding elegance to the frock. The lightweight nature of cotton satin ensures breathability and ease of movement, perfect for children's clothing.

Square Neckline: The frock could feature a chic and modern square neckline, adding a touch of sophistication to the design. The square neckline frames the shoulders beautifully and offers a flattering silhouette. It's a versatile neckline that suits various body types and ages.

Gathered Design: Incorporate a gathered waistline to add volume and create a charming silhouette. The gathered waist can be emphasized with a coordinating fabric belt or bow in light green, adding visual interest and defining the waist.

Sleeveless Design: A sleeveless design is ideal for warmer weather or indoor events, allowing freedom of movement and keeping the child cool and comfortable. The absence of sleeves also adds a youthful and playful vibe to the frock.

Details: Consider adding delicate embellishments such as floral embroidery, lace trims, or fabric appliqués in light green to enhance the overall beauty of the frock. These details can be strategically placed along the neckline, waistline, or hem for a touch of elegance.

Overall, a gathered frock with a square neckline and sleeveless design in white and light green would be a charming and stylish choice for any occasion, whether it's a casual outing or a special event. The combination of luxurious fabric, modern neckline, and refreshing color palette creates a timeless ensemble that any little one would love to wear.