胎盘绿色素：由血红蛋白而来的位于胎盘内的绿色物质- Armillifer
- Armophorina
- armpit
- Arnaldus de Villanova
- Arndt's law,Arndt-Schulz law
- Arneth's count (classification,formula,in-dex)
- Arnica
- arnica
- A.R.N.M.D.
- Arnold-Chiari deformity(malformation,syndrome)
- Arnold of Villanova,Arnaldus de Villanova
- Arnold's bodies
- Arnold's canal,etc.
- arnotto
- A.R.O.
- AROA
- aroma
- aromatase
- aromatic
- aromatic-L-aminoacid decarboxylase
- aromatization
- aromine
- arousal
- arprinocid
- arrachement