Brihat Parashara Hora Shastra
षष्टिर्वक्रगते वीर्यमनुवक्रगतेर्दलम् । पादो विकलभुक्तेः स्यात् तथा मध्यगतेर्दलम् ॥ २२॥
These are Vakr (retrogression), Anuvakr (entering the previous Rāśi in retrograde motion), Vikal (devoid of motion), Mand (somewhat slower motion than usual), Mandatar (slower than the previous), Sama (somewhat increasing in motion), Char (faster than Sama) and Atichar (entering next Rāśi in accelerated motion).
english translation
SaSTirvakragate vIryamanuvakragaterdalam । pAdo vikalabhukteH syAt tathA madhyagaterdalam ॥ 22॥
hk transliteration by Sanscript