Sepals, also known as calyx, are green leaf-like structures located below the petals in a flower. The primary function of sepals is to protect the developing bud before it blooms. Other words that can be used synonymously with sepals include calyces, perianth, and tepals. Calyx is used interchangeably with sepals, but it is important to note that calyx refers to all sepals in a flower and can have a different color than green. Perianth refers to the outer parts of a flower that include both the sepals and the petals, while tepals refer to indistinguishable petal-like structures that can have the same color and texture as sepals.