It depends
Unqualified "starch" on a US packaged food means cornstarch — that is the default the FDA's standard of identity assumes, and anything else has to be named. The caution is the same one that applies to modified food starch: on a USDA label, covering meat, poultry and egg products, the naming rules are looser and a bare "starch" carries less of a promise. A product that also makes a gluten-free claim settles it either way.
Because the answer depends on the rest of the label, scanning the actual product is the only way to resolve it — CiCi checks for a gluten-free claim, the allergen statement, and which agency regulates that label, then tells you which way it lands.
Point CiCi at the barcode on the product you're holding and get this same reasoning in about two seconds, plus the carbs and the full nutrition panel. 360,000+ packaged foods are already read and waiting.
This answer comes from CiCi's ingredient lexicon — the same rules the scanner uses, not a separate article. Where reputable sources disagree, CiCi takes the conservative position and says so.