sleep-related accidents, SRBD (sleep-related breathing disorders), sleep-related eating disorders, sleep-related symptoms, sleeptalking (talking in sleep e.g. during stage REM
sleep), sleepwalking (somnambulism), SL (sleep latency), slow eye movements,
SNA angle (sella-nasion-subspinale angle), SNB angle (sella-nasion-supramentale angle), snoring,  snoring sound test, SO (sleep onset), SOREM (sleep onset REM), somnolence, somnoplasty, sphincteroplasty, spiltnight PSG, split-night sleep study, split-night study, SpO2 (percutaneous oxygen saturation, or pulse oximetry saturation), SRBD (sleep-
related breathing disorder), SRH (sleep related hypoventilaiton), SRH due to a
medication or a substance, SRH due to a medical disorder, sleep related hypoxemia, 
sleep stages (N1, N2, N3, R) [NB. Stage W = awake stage], SSI (Stanford Center for Narcolepsy Sleep Inventory), SSS (Stanford sleepiness scale), standard
polysomnography, stiffening, submucosal lossectomy, submucosal lingualplasty,
submucosal minimally invasive lingual excision (SMILE), submucosal uvulopalatopharyngoplasty, SUDS (sudden unexplained death syndrome), SUNDS sudden unexplained nocturnal death syndrome (SUNDS), supplemental oxygen,
suprarachiasmatic nucleus, supraglottic, supraglottoplasty, SWP (sleep wake disorder/s), SWPD (sleep wake phase disorders e.g. circadian sleep-wake disorder not otherwise specified), delayed SWD, advanced SWD, shift work disorder, jet lag disorder), SWS (slow wave sleep), synchronization, T (temporal), TCO2 (transcutaneous carbon dioxide level) , thermister, thermocouple, The AASM Manual for the Scoring of Sleep and Associated
Events (i.e. rules, terminology and technical specifications - version 2.1 etc.), Theta waves, tidal volume, TIB (time in bed), TMN (tuberomammillary nucleus), TMT (total
movement time), TREM (total REM time), time axis, titration, tongue-tie, tonsil, tonsillectomy, total recording time (TRT), tracheostomy, tracheotomy, transcutaneous
CO2, transcutaneous carbon dioxide monitor, transducer, transient arousal,
transmembrane potential, transpalatal advancement pharyngoplasty, transpalatal, treatment-related factors, treatment-emergent CSA, tricyclic antidepressants, TRT (total recording time), Ts (bilateral tonsillectomy), TSW (total slow wave sleep- N3), TST (total sleep time), TT (total time), Tx (treatment), TWT (total wake time), UARS (upper airway resistance syndrome), unintended sleep episode, UPF (uvulopalatal flap), upper airway anatomy, upper airway compliance, upper airway dynamic imaging, upper airway
imaging, upper airway videoendoscopy, UPPP/UP3 (uvulopalato-pharygoplasty), uvula, uvulectomy, UP (uvulopalatoplasty), UPF (uvulopalatal flap),  VPI (velopharyngeal insufficiency), ventilation catheter, videoendoscopy, VLPO (ventrolateral preoptic
nucleus), VPAP (variable positive airway pressure, VPI (velopharyngeal insufficiency),
VRG (ventral respiratory group), VT (ventricular tachycardia), VTA (ventral tegmental
area of midbrain), V waves, XPAP (any type of positive airway pressure device), WT
(wake time), WASO (wake after sleep onset), weight reduction, Wisconsin Sleep Cohort Study, Woodson, YAWN (young Americans with narcolepsy).