1) By a factor of three 2) Exclusively Saxon word 3) Exclusively Anglo word 4) Like a $6 return on a $2 bet 5) Multiple 6) Three times as great or many 7) Treble 8) Triple 9) Word with Anglo-Saxon origins 10) Word of purely Anglo origin 1) Double 2) Multiple 3) Sino 4) Ternary 5) Treble 6) Trinal 7) Trinary 8) Trine 9) Triple 10) Triply 11) Twofold 
• (a.) Consisting of three, or thrice repeated; triple; as, threefold justice.
Three'fold` adjective [ Middle English þreofald ; confer Anglo-Saxon þrīfeald .] Consisting of three, or thrice repeated; triple; as, threefold justice. « A threefold cord is not quickly broken.» Eccl. iv. 12. 
[adv] - by a factor of three
adverb by a factor of three; `our rent increased threefold in the past five years`