Most of them aren't defined as rigorously as a dictionary would do, it's more like trying to come up with a plausible description for each word.

"day" might be "time in which the sun goes round the earth" even though that's not technically correct.

"sit" could be "to take a chair" and "sat" might be "to have took a chair"

"moth" is "a bug that flies and likes to eat cloth", and so on.