Explanation

ALLAH is Al-Mateen, The One who is most steadfast and solid, The One who is loyal, firm, and constant, The One whose nature is the utmost firmness and steadfastness, The One who can easily overcome anything through supreme firmness and strength of determination.

From the root word meem-ta-noon we derive various classical Arabic connotations such as to be strong, stout, firm, hard, to be solid, robust, to be steadfast, certain, sure, to possess any quality in a strong degree, the hard outer or apparent part of something and elevated and hard ground.

Quran References

Indeed, it is Allah who is the [continual] Provider, the firm possessor of strength.  (Quran 51:58)