Russian-English translations for твёрдость

• determination
  Through sheer determination, we managed to escape from the tornado
  a determination of blood to the head
  the determination of the wavelength of light
• firmness
• hardness
• resolution
  His stalwart resolution is perhaps admirable, perhaps foolish
  By February, most New Years resolutions are forgotten.   My resolution is to cut back on the fast food this year
  Printing at higher resolution will cause a reduction in performance
• solidity
• solidness
  When something melts it loses its solidness and becomes a liquid.
• steadfastness