[1855–60; declin(ation) + -o- + -meter]This word is first recorded in the period 1855–60. Other words that entered Englishat around the same time include: boilerplate, keyword, lavabo, pipeline, superheat-meter is a combining form meaning “measure,” used in the names of instruments measuringquantity, extent, degree, etc. Other words that use the affix -meter include: chronometer, gravimeter, nephelometer, radiometer, telemeter