\Te*nac"i*ty\, n. [L. tenacitas: cf. F. t['e]nacit['e].
See {Tenacious}.]
1. The quality or state of being tenacious; as, tenacity, or
   retentiveness, of memory; tenacity, or persistency, of
   purpose.
2. That quality of bodies which keeps them from parting
   without considerable force; cohesiveness; the effect of
   attraction; -- as distinguished from brittleness,
   fragility, mobility, etc.
3. That quality of bodies which makes them adhere to other
   bodies; adhesiveness; viscosity. --Holland.
4. (Physics) The greatest longitudinal stress a substance can
   bear without tearing asunder, -- usually expressed with
   reference to a unit area of the cross section of the
   substance, as the number of pounds per square inch, or
   kilograms per square centimeter, necessary to produce
   rupture.