R

= Range,范围，区域，量程，波段;

= Ratio, 比，比率;

= Read，Reader, 读；读出器；读程序;

= Receipt, 收据;

= Receiver, 接收机;

= Record, 记录;

= Register, 寄存器;

= Repeat, 重发，反复，重复;

= Reset, 复位；置"０";

= Resistance, 电阻;

= Resistor, 电阻器