poetic or archaic shortening of 'beneath,' meaning under or below.
From Middle English contraction of 'bi-neathan.' 'Neath' is a poetic abbreviation that survives mainly in poetry and song lyrics today.
"Neath the bough' sounds more musical than 'beneath the bough'—poets deliberately chose this contraction because the missing syllables made their meters work better, showing how language bends to fit rhythm.
Complete word intelligence in one call. Free tier — 50 lookups/day.