syrup
In Korean cooking this usually means a light starch or rice syrup (mulyeot, jocheong): thick, mildly sweet, and used for gloss.
Korean recipes mostly call for a light starch syrup or rice syrup, which is less sweet than sugar and gives glazes and stir-fried dishes their shine and cling. It is sold in Asian grocery stores; glucose syrup is also found in the baking aisle of many supermarkets, and rice syrup in health food stores.
Substitute:
Glucose syrup or light corn syrup come closest to the original, as does rice syrup. Honey or agave syrup also work but are noticeably sweeter and bring their own flavour, so use less; sugar dissolved in water sweetens but gives little gloss or body.