Source : Webster's Revised Unabridged Dictionary (1913)

Lengthen \Length"en\ (-'n), v. t. [imp. & p. p. {Lengthened}
   (-'nd); p. pr. & vb. n. {Lengthening} (-'n*[i^]ng).]
   To extent in length; to make longer in extent or duration;
   as, to lengthen a line or a road; to lengthen life; --
   sometimes followed by out.

         What if I please to lengthen out his date. --Dryden.

Source : WordNet®

lengthened
     adj : drawn out or made longer spatially; "Picasso's elongated Don
           Quixote"; "lengthened skirts are fashionable this
           year"; "the extended airport runways can accommodate
           larger planes"; "a prolonged black line across the
           page" [syn: {elongated}, {extended}, {prolonged}]