Lengthen /(-'n)/

Length·en

Lengthen

v. t.

imp. & p. p. Lengthened; p. pr. & vb. n. Lengthening

  1. 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.

Lengthen

v. i.
  1. To become longer.