late 15c., "symbol, emblem," from Latin typus "figure, image, form, kind," from Greek typos "dent, impression, mark, figure, original form," from root of typtein "to strike, beat," from PIE root *(s)teu- "to strike, cut, hew" (see steep (adj.)). Extended 1713 to printing blocks with letters carved on them. The meaning "general form or character of some kind, class" is first in English 1843, though it had that sense in Latin and Greek. To be someone's type "be the sort of person that person is attracted to" is recorded from 1934.
Another option for structural-integrity monitoring is "non-contact monitoring", which uses the Doppler effect (Doppler shift). A laser beam from a Laser Doppler Vibrometer is directed at the point of interest, and the vibration amplitude and frequency are extracted from the Doppler shift of the laser beam frequency due to the motion of the surface.  The advantage of this method is that the setup time for the equipment is faster and, unlike an accelerometer, this makes measurements possible on multiple structures in as short a time as possible. Additionally, this method can measure specific points on a bridge that might be difficult to access.