Here's what rhymes with arclength.
                        
                        
                    
                                Words that almost rhyme with arclength
lens  tenth  cleanse  glens  sense  hence  dense  thence  whence  fence  tense  tens  gems  hens  pence  pens  dens  gens  fens  hems  immense  offence  offense  stems  commence  theorems  harems  defence  defense  expense  intense  incense  condemns  pretense  condense  morphemes  recommence  dispense  suspense  recompense  sixpence  halfpence  twopence  commonsense  frankincense  length  death  health  wealth  breath  depth  breadth  neath  strength  stealth  twelfth  shibboleth  commonwealth