Definition of Thyroid cartilage

Thyroid cartilage: The largest of the cartilages of the larynx (the voice box).

The thyroid cartilage is formed of two approximately quadrilateral plates (called laminae) that are joined anteriorly (in the front) at an angle of from 90° to 120° to create a prominence in the neck.

This bump is called the laryngeal prominence (or, familiarly, Adam's apple). The thyroid cartilage has nothing to do with the thyroid gland, except for proximity.