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1. The degree of firmness of a solid, as determined by its resistance to deformation, scratching, or abrasion.
See also: hardness scale, number.
2. The relative penetrating power of a beam of x-rays, used both within the diagnostic range of energy and in radiation therapy; expressed in terms of half-value layer.


Etymology: AS, heard, hard
1 a quality of water produced by soluble salts of calcium and magnesium or other substances that form a precipitate with soap and thus interfere with its cleansing power.
2 the quality of firmness produced by cohesion of the particles composing a substance, as evidenced by its inflexibility or resistance to indentation, distortion, or scratching.


1. The degree of firmness of a solid, as determined by its resistance to deformation, scratching, or abrasion.
2. The relative penetrating power of a beam of x-rays.

Patient discussion about hardness

Q. Why is it so hard???? Why is it so hard to quit drinking ? i try and i try and it seems like i can't find the strength to stop completely .. every time i am almost there .. but than i just snap!

A. HI....find out about alcoholics anonymous in your town,call their 800#...go to(INTHEROOMS.com)find HELP.......mrfoot56

Q. i cant stop getting a hard on erection stiffy embarrassing crease in trousers

A. Have you heard of priapism,a condition in which the penis is continually erect; usually painful and seldom with sexual arousal. If you suffer from this you should go see a doctor about it.

Q. anyone knows how to stop hard skin on the feet from becoming cracked??? during summer my feet got lots of hard skin and in the heel area the skin actually got cracked kinda deep. it hurts now and the cracks are starting to get infected I guess... do u guys know how to solve this?? I know there are some creams for that but I thought maybe now it's too late for that and I need something stronger?

A. There are good creams for moisterizing the skin of your feet on a daily basis, however now that you feel they might be infected you should see a dermatologist for some better treatment.

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References in periodicals archive ?
Statistical Analysis of Color Value: The statistical analysis of variance for color value of the dyed cotton knitted fabric in five hardness levels is given in Table 1.
Sample###Area###Total Hardness as CaCO3 (mg/L)###pH
The presented work deals with relatively more reliable and accurate hardness analysis in heterogeneous structures engineering.
The mean of the sum of indentations per surface was calculated to have one representative reading for both the bottom and top surface hardness.
The T6 or T61 heat treatment (solution, quench and age) also can be modified to improve the hardness.
Test of hardness according to Vickers is prescribed by European standard CSN EN ISO 6507-1.
Anti-pulling intensity and surface hardness of bamboo leaf is maximal, which is dicided by its cell structure and composites of epicuticular cell.
5 hardness measurements have been carried out in each area at identical intervals and their arithmetic mean value is presented for the report.
In terms of actual hardness, diamond is four times harder than corundum.