accelerograph

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An accelerometer equipped to measure and record ground motion during an earthquake.

from The Century Dictionary.

• noun An apparatus designed for measuring the succession of pressures developed in a powder-chamber by the combustion of a charge.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Mil.) An apparatus for studying the combustion of powder in guns, etc.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun military An apparatus for studying the combustion of powder in guns, etc.
• noun geology An instrument used to record the acceleration of the ground during an earthquake.