The propanoate or propionate ion is C2H5COO− (propanoic acid minus one hydrogen ion).
A propanoic or propionic compound is a salt or ester of propanoic acid.
Propanoates should not be confused with propenoates (commonly known as acrylates), the ions/salts/esters of propenoic acid (also known as 2-propenoic acid or acrylic acid).