There are multiple definitions:

1. Reading the Mind in the Eyes [Revised](English)

   • to measure autistic traits
   • AQ, ASD, GD, GIDYQ, IQ, KS, HC, SCL-90-R, SAST
   • Psychology
   • https://doi.org….1111/jsm.13048

2. rapid maxillary expansion(English)

   • used to expand the narrow maxilla
   • ANS, CBCT
   • Dentistry
   • https://dx.doi.…nals-10005-1069
   • https://doi.org…rge.2014.04.005

3. relative motion extension(English)

   • ECM, FO, MCP, TAM, WHFO
   • Shoulder and other joints
   • https://doi.org…jht.2023.02.010