An Etymological Dictionary of Astronomy and Astrophysics

1. The quality of being just; righteousness, equitableness, or moral rightness.
   

2. The moral principle determining just conduct.
   

3. The administering of deserved punishment or reward (Dictionary.com).

Etymology (EN): M.E., from O.Fr. justice “justice, legal rights, jurisdiction,” from L. iustitia “righteousness, equity,” from iustus “upright, → just.”

Etymology (PE): Dâd “justice, law” from Mid.Pers. dâd “law, justice, scriptures with legal content;” related to Mid.- and Mod.Pers. daheš “creation,” dâdan “to give;” Av. dā- “to place upon, give;” → datum.
Dâdmandi noun from dâmand, → just.
Dâdgari “administration of justice,” from dâdgar, literally “just doer,” “an administrator of justice,” from dâd + -gar, → -or.
Dâdgostari, from Dâdgostar, literally “justice spreader,” with gostar, from gostardan “to spread, → expand.”