Here's why:

* Chemical Formula: Ca(OH)₂

* Dissociation in Water: When dissolved in water, calcium hydroxide dissociates into calcium ions (Ca²⁺) and hydroxide ions (OH⁻). The presence of hydroxide ions (OH⁻) is the defining characteristic of a base.

* pH: Solutions of calcium hydroxide have a pH greater than 7, which is another indication of a base.

Other terms for calcium hydroxide:

* Slaked lime: This is a common name for calcium hydroxide.

* Hydrated lime: This name emphasizes that the compound contains water molecules.

Let me know if you have any other questions.