A wireframe is a sketch-like representation of screens and sometimes also their interconnections. They often used during UX design to communicate ideas or as a form of low-fidelity prototype.
Used in glossary entries: low-fidelity prototype, user experience design
Links:
figma.com: Figma: What is wireframing?- canva.com: Canva: Free Online Wireframe Tool
Wireframe of a single screen. Source: Maryana (WMF), CC BY-SA 3.0, via Wikimedia Commons
Wireframe showing flow between screens. Source: (portion of) Lindsey Smith, CC BY-SA 3.0 , via Wikimedia Commons