Ledled is a new word, and lists "everywhere" as valid in the hover-text, but was marked as wrong. It said "throughout" was the only valid answer.
'throughout' and 'all over' are the usual meanings. We will delete 'everywhere' from the hints for ledled.
Thank you for noticing.
Would one also use 'ledled' for describing something that had spread 'all over' the place?
Depending in the context, yes. There may be some good examples here - https://mymemory.translated.net/en/Welsh/English/Ledled - although that site does suffer from occasional nonsense and vandalism among the valid and useful translations. The good translations tend to be in more formal Welsh than this course covers, though.