natu - obsc
- natural
- natural asphalt
- natural circulating water cooling
- natural circulation
- natural cooling
- natural current
- natural draft / draught
- natural draught cooling tower
- natural dye
- natural frequency
- natural gas
- natural lighting
- natural logaritm
- natural magnet
- natural mositure content
- natural motion / oscillation / vibration
- natural period
- natural rubber
- natural ventilation
- nature
