Final answer:
A molecule that is capable of releasing or donating a hydroxyl ion is called a base.
Step-by-step explanation:
A molecule that is capable of releasing or donating a hydroxyl ion is termed a base. Bases can release hydroxide ions (OH-) in solution or accept H+ ions already present in solution. An example of a base is NaOH, which contains the hydroxide ion and can accept a proton from an acid to form water.