1. Membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional
   - yolk sac, vitelline sac, umbilical vesicle

Type of: sac

• Scindapsus aureus
• scintilla
• scintillant
• scintillate
• scintillating
• scintillating scotoma
• scintillation
• scintillation counter
• sciolism
• sciolist
• sciolistic
• scion
• Scipio
• Scipio Africanus
• Scipio Africanus Major
• Scipio the Elder
• scire facias
• scirocco
• Scirpus
• Scirpus acutus
• Scirpus cyperinus
• scissile
• scission
• scissor
• scissor grip