A disaccharide is formed when two monosaccharides combine with each other via dehydration synthesis reaction.
The covalent bond so formed between the two monosaccharides is called glycosidic bond. Refer to Concept - 7 for more information on dehydration synthesis
The common types of disaccharides are grain sugar maltose, made of two glucose molecule, the milk sugar lactose, made of a galactose and a glucose molecule , the table sugar sucrose, made of a glucose and a fructose molecule
Both maltose and sucrose have glycosidic bonds as they are disaccharides.