The definition of countless is too many to be counted or too numerous to measure.
The blades of grass spread across the entire earth are an example of something that would be described as countless.
Too many to be counted; innumerable. See Synonyms at incalculable.
count + -less
- He had twenty assassins to rescue and countless souls waiting to be claimed.
- I ruled Death's domain for countless millennia.
- Exactly. Victor is responsible for the deaths of countless werewolves.
- Chmielnicki's conditions of peace were so extravagant that the Polish commissioners durst not accept them, and in 1649 he again invaded Poland with a countless host of Cossacks and Tatars.
- The exciting and profitable occupation of blockade-running led to countless small fights off the various harbours, and sometimes the United States navy had to fight a more serious action when some new "rebel" ironclad emerged from her harbour, inlet or sound.