See Also:

thorough(2) (iou)



thorough preposition & adverb.
[Old English Turuh, disyllabic alt. of Turh THROUGH preposition & adverb, paralleled in borough, furrow, marrow, sorrow.]
A. preposition. = THROUGH preposition. OE-L19.
b. adverb. = THROUGH adverb. Now only (obsolete exc. dial.), thoroughly (cf. THROUGH adverb 3). OE.