An archaic adverb meaning 'on a reel' or 'spinning', now obsolete.
From 'a' (on, in) + 'reel' (a spinning object). Old English/Middle English construction pattern.
Like 'areek', areel shows the old 'a-' prefix pattern—if you said 'a-whirling' or 'a-turning' today you'd sound like Shakespeare, but that was regular English in the 1300s!
Complete word intelligence in one call. Free tier — 50 lookups/day.