- exhibiting a gap between the teeth, especially between the two upper central incisors
- exhibiting a gap where a tooth is missing, as of a child who has lost a baby tooth, or an adult who has lost a permanent tooth
2011, David F. Bjorklund, Carlos Hernández Blasi, Child & Adolescent Development: An Integrated Approach, ISBN 049509563X, page 141–42:
- The gap-toothed grins of many 7- and 8-year-olds reflect the rapid loss of baby teeth and eruption of permanent teeth during the early school years, although children typically do not lose all of their primary teeth until they are about 12 years old.
having a gap between the front teeth