Stamina is the strength to keep going after the first burst has gone. The runner still moving at mile twenty, the parent on the fourth hour of a children's party, the student on the last essay of a long week.
It is uncountable — you have stamina, you build stamina, you run out of stamina, but there is never a stamina and never staminas. It covers the mind as much as the body: physical stamina for the hill, mental stamina for a nine-hour negotiation. Keep it apart from strength, which is what you can lift in one heave. Stamina is how long you can keep lifting. The words that go with it are build, lack, have, and the phrase staying power says the same thing in plainer English.
1nounstaminaThe physical or mental strength to keep doing something tiring for a long time.
“Cycling to work every day gave him stamina he never had before.”
synonyms: endurance, staying power
stamina is a form of endurance.
Also accepted in games: endurance
Stamina is a Latin plural pretending to be a single thing. Latin stāmina is the plural of stamen — the word botany still uses for the thread-like parts inside a flower — and it grows from the ancient root *steh₂-, to stand. English swallowed the plural whole and turned it into one uncountable quality, so what began as several threads is now a single thing you either have or run out of.
Proto-Indo-European
*steh₂-
Latin
stāmina
English, today
stamina
From Latin stāmina, plural of stamen.
Etymology from Wiktionary, CC BY-SA