return spring,复位彈簧

return-to-zero (RZ),歸零制

reverberant field,混響聲場

reverberation room,混響室

reverse action,反作用

reverse actuator,反作用執行机构

reverse bend tester,彎折試驗机

revers osmosis method for desalination,反滲透淡化法

reverse search,逆譜庫檢索

reverse video,反相顯示

reversed-phase column,反相柱

reversed-phase liquid chromatography,反相液相色譜法

reverser,反向器

reversing thermometer,顛倒溫度表

revising method of (thermal) electromotive force,（熱）電動勢修正法

revisit rate,回訪速率

revolution speed,轉速

revolution speed check table,轉速校驗台

revolution speed transducer,轉速傳感器

Reynolds number,雷諾數

RF-presentation,射頻顯示；不檢波顯示

rhodium-iron resistance thermometer,銠鐵電阻

rigid disk drive,硬磁盤机

rigid polyvinyl chloride,硬聚氯化烯

rigid rotor,剛性轉子

ring balance,環秤

ring balance manometer,環秤壓力計

ring-down pulse,振鈴脈衝

ring network,環形网絡

ring viscometer,環式粘度計

ringing frequency,自振周期

ringing period,自振周期

ripple,紋波

ripple coefficient of voltage,電壓紋波系數

ripple voltage,紋波電壓

rise time,上升時間

rise-time discrimination,上升時間鑒別

risk analysis,風險決策

risk evaluation,風險評价

robot,机器人

robot programming language,机器人編程語言

robot system,机器人系統

robotics,机器人學

robust control,魯棒控制

robust controller,魯棒控制器

robustness,魯棒性

rock densitometer,岩石密度計

rock pression sclerometer,岩石壓入硬度計

rocketsonde,火箭探空儀

Rockwell hardness number,洛氏硬度值

Rockwell hardness penetrator,洛氏硬度壓頭

Rockwell hardness tester,洛氏硬度計

Rockwell superficial hardness number,表面洛氏硬度值

Rockwell superficial hardness tester,表面洛氏硬度計

rod anode X-ray tube,棒陽极X射線管

rod of pendulum,擺杆

roentgen,倫琴

Roland circle,羅蘭圓

roll chart [paper],卷筒式記錄紙

roll-gap,輥縫

rolling chains,滾鏈

rolling diaphragm actuator,滾動膜片執行机构

rolling sphere viscometer,滾球式粘度計

rolling test,滾動試驗

root mean square (RMS) detector,均方根檢波器

Roots flowmeter,腰輪流量計

rosette sampling system,多袋采水器

"rotary"displacement meter,﹛旋轉﹛排量式儀表

rotary eccentric plug valve,偏心旋轉閥

rotary motion valve,角行程閥

rotary pump,机械泵

rotating beam apparatus,旋臂裝置

rotating-beam ceilometer,旋轉波束云高計

rotating-beam cloud height meter,旋轉波整束云高計

rotating cylinder viscometer,旋轉圓筒式粘度計

rotating magnetometer,旋轉磁力儀

rotating [oscillating] piston flowmeter,旋轉活塞流量計

rotating target X-ray tube,旋轉陽极X射線管

rotating vibration generator,回轉振動器

rotation magnetic field,旋轉磁場

rotation magnetization,旋轉磁化

rotation or vibrating coil magnetometer,旋轉或振動線圈磁強計

rotational distortion,旋轉畸變

rotational viscometer,旋轉粘度計

rotative speed,轉速

rotative speed difference,轉速差

rotor,轉子

rotor axis,轉子軸線

rotor flow transducer [sensor],轉子流量傳感器

rotor gear,轉子齒輪

run of wind,風程

run-of-wind anemometer,風程表

running means,滑動平均

round trip propagation time,往返傳播時間

routine,例行程序

routine tese,出厂檢驗；例行試驗

rupture pressure,破坏壓力

rustpreventive packaging,防鏽包裝