Camiknickers is a name for women's underwear that is basically a camisole and knicker set combined into one garment. The term camiknickers is generally used to refer to the antique style garment. The full all in one undergarment worn during the 1920s is more generally called a Step-in, while the more modern combo is likely to be called a Teddy.
Antique camiknickers may have the old style vertically split crotch or a rear trap door closure, step-ins may be pull on or have snaps at the crotch, and a teddy will usually have snap fasteners at the crotch.
Antique Camiknickers with rear trap door
1950s Teddy with snap crotch closure