1 DX-format, normal single-focal-length lens with 35mm focal length (picture angle is equivalent to a focal length of 52.5mm in FX and 35mm formats)  Large maximum aperture of f/1.8.
http://imaging.nikon.com/lineup/lens/singlefocal/normal/af-s_dx_35mmf_18g/
Comparison of image sensor sizes, including Nikon DX. The Nikon DX format is an alternative name used by Nikon corporation for APS-C image sensor format being approximately 24x16 mm. Its dimensions are about 2⁄3 (29 mm vs 43 mm diagonal, approx.) those of the 35mm format. The format was created by Nikon for its digital SLR cameras, many of which are equipped with DX-sized sensors. DX format is very similar in size to sensors from Pentax, Sony and other camera manufacturers. All referred to as APS-C including the slightly smaller Canon cameras. Nikon has produced 23 lenses for the DX format, from macro to telephoto lenses.
https://en.wikipedia.org/wiki/Nikon_DX_format
The good news is that not all DX lenses behave as you might expect. Two DX lenses that I dearly love are my Nikon 35mm f/1.8G DX and my Tokina 11-16mm f/2.8 AT-X Pro DX. These two represent the best of DX as they are small, fast, light and affordable, yet still perform excellently.
https://photographylife.com/using-nikon-dx-lenses-on-fx-cameras/
Midrange film zooms got no wider than 24mm, which only gave a normal angle of view on DX cameras. Nikon also introduced various DX midrange zooms starting at 17mm or 18mm, which due to the crop factor, were zooms which started out with a field of view similar to what a 28mm lens sees on a 35mm film or FX camera.
http://www.kenrockwell.com/nikon/dx-lenses.htm
Lenses designed for Nikon DX generally project a smaller image circle because they only need to cover the smaller DX sensor. This enables a DX lens to be smaller and lighter, but also means that these lenses are not suitable, by design, for FX cameras. For the Canon ecosystem this law is absolute, as EF-S lenses, designed for a smaller APS-C size sensor, cannot be mounted on full frame EF bodies.
https://photographylife.com/using-nikon-dx-lenses-on-fx-cameras/
Nikon 35mm f/1.8G DX on FX. Until recently, the only fast modern 35mm lens that Nikon offered for FX was the expensive professional 35mm f/1.4G prime. With the recent announcement of the 35mm f/1.8G ED the situation has improved a lot from the affordability perspective.
https://photographylife.com/using-nikon-dx-lenses-on-fx-cameras/
In the beginning, Nikon made 35mm film cameras. They shot film with an image size of 24 x 36mm. In 1999 Nikon brought forth DX digital cameras, which used digital image sensors which were 1.5x smaller than 35mm film. Until 2003, Nikon's widest zoom was the 17-35mm f/2.8, an $1,800 two-pound lens.
http://www.kenrockwell.com/nikon/dx-lenses.htm
Disadvantages of 35mm lenses include generally higher weight and incompatible features such as autofocus with some lower-end DX cameras. Nikon has also produced digital SLRs that feature the larger Nikon FX format sensor that is the size of the 135 film format. In 2013, Nikon introduced a high-end compact camera with a DX-sized sensor, the Nikon Coolpix A, featuring an 18.5 mm lens.
https://en.wikipedia.org/wiki/Nikon_DX_format
Nikon's DX lenses are lenses which only cover the smaller sensor of DX digital cameras. DX lenses have reduced capacity compared to regular lenses. Used on a film or full-frame sensor, at some or all settings they will black-out in the corners.
http://www.kenrockwell.com/nikon/dx-lenses.htm
1 DX-format, normal single-focal-length lens with 35mm focal length (picture angle is equivalent to a focal length of 52.5mm in FX and 35mm formats) 2  Large maximum aperture of f/1.8.  Silent Wave Motor (SWM) ensures smooth AF operation.
http://imaging.nikon.com/lineup/lens/singlefocal/normal/af-s_dx_35mmf_18g/
what size is the lens on my nikon dx
The size of the lens in the Nikon Dx is 35 millimetre.