1. At night
   "nocturnally active bird"

See also: nocturnal

• sustaining program
• sustainment
• sustenance
• sustentacular
• sustentation
• sustentative
• susurrant
• susurrate
• susurration
• susurrous
• susurrus
• Sutherland
• sutler
• sutra
• suttee
• sutura
• sutura coronalis
• sutura frontalis
• sutura intermaxillaris
• sutura internasalis
• sutura lamboidea
• sutura sagittalis
• sutural
• sutural bone
• suture