What did you have to look up
It is not impossible this was a gentle tongue-in-cheek poke at my repeated complaints about non-explained codes, acronyms, abbreviations, and then applying one myself. If it were, I would sadly have to admit a hit, smilingly though. So here goes, for the uninitiated: NORDO is aviators' short for "No Radio".
And while we're at it, there's a surprising number of PPL'ers who take the presence and active use of radio as self-evident - while in truth it is only mandatory in controlled airspace, and at certain fields who publish the requirement, in France for example.