Parliament passes (принимает) domestic laws and President signs them afterwards in order to enact these laws. However, it is President who first signs international treaties and the like with other contries. But in order to give them the legal force Parliament needs to approve these agreements. This procedure of official approval via voting by Parliament is called ratification (ратификация).IMO
Ратифицирование is a valid synonym of ратификация, a little bit less common in usage though.
ратифицирование — ВикисловарьЗначение -
юр., полит. действие по значению гл. ратифицировать; официальное утверждение чего-либо, придание чему-либо юридической силы