The term alveolar is used to describe a sound which is articulated at the alveolar ridge, which is between the teeth and the hard palate. Examples of alveolar sounds are /t/ as in tip, /d/ as in dip, /s/ as in sip, /z/ as in zip, and /n/ as in nip.
Pertaining to the alveoli, the tiny air sacs in the lungs. The exchange of oxygen and carbon dioxide takes place in the alveoli which look like cells in a honeycomb. See the entire definition of Alveolar