Basicity refers to the number of replaceable hydrogen ions (H\(^+\)) an acid molecule can furnish in a solution.

The basicity of oxalic acid (C\(_2\)H\(_2\)O\(_4\)) is 2, meaning it's a dibasic acid because each molecule can donate two protons (H\(^+\)) when ionized in water, forming two replaceable hydrogen atoms and reacting with two moles of hydroxide ions, allowing it to form normal salts like K\(_2\)C\(_2\)O\(_4\).