Acids and Bases
They are both substances. They also are groups of hydrogen(Acid) and Hydroxide ions(Bases). If you add them together you get table salt and water.
H+ + OH- = H2O and NaCl
They are also different. They are made up of different ions. Acids taste sour and Bases taste Bitter. Acids are mainly fruit where as Bases are mainly farm products like milk and eggs.