is an abbreviation of "after recording" (source: ).
"wasei" literally means "Japanese-made". It's a term used to describe words that were made in Japan, despite being made out of foreign words. For example, "wasei eigo" means "Japanese-made English". ~~Another famous example of wasei eigo is "salaryman", which despite seeming like an English word, is only used in Japan.~~ (Apparently not quite! See Eiríkr's comment.)