Description:The specific amino acid position in a protein or peptide sequence designating a potential or actual covalent attachment of a monosaccharide, oligosaccharide, or polysaccharide/glycan to: 1) a nitrogen atom, usually of asparagine (N-linked); 2) an oxygen atom of a serine, threonine, hydroxyproline or hydroxylysine residue (O-linked); 3) a carbon atom of a tryptophan residue (C-linked); or 4) a sulfur atom of cysteine (S-linked) to perform a structural and/or functional role in the resulting glycoconjugate.