Is it ensure, insure, or assure?
late Old English anon, earlier on an, literally "into one," thus "continuously; straightway (in one course), at once;" see one. By gradual misuse, "soon, in a little while" (1520s). A one-word etymological lesson in the enduring power of procrastination.
An abbreviation for anonymous, used to indicate unknown or unacknowledged authorship. Without the period, anon means “at another time” or “again.”