A7r5 stands for Smooth Muscle Cell Line
A7F stands for Avenged Sevenfold (band)
A51 stands for Area 51
A4ID stands for Advocates for International Development
A549 stands for human alveolar epithelial cells
A5F stands for Anti Five Finger
A5K stands for Audi 5000 (car model) A5K stands for Audio 5000 Ohm (variable resistor with an audio taper)
A3C stands for Airman Third Class
A6 stands for Atmosix
A4T stands for Apple for Teacher