There are multiple definitions:

1. space-occupying lesion(English)

   • Pathology

2. sleep onset latency(English)

   • DMH, EEG, LC, REM, ROL, SCN, SFA, TMN, vSPZ
   • Sleep medicine, Circadian rhythm, Hormone, Endocrinology, Gynecology
   • https://doi.org…155/2010/259345