What does "tundra" mean?

A flat and treeless Arctic biome.

Tundra

Common synonyms include: alaska, alkali flat, alluvial plain, antarctic zone, antarctica, arctic circle.

//ˈtʌndɹə// name, noun

name, noun ·Moderate ·College level

Noun

1
A flat and treeless Arctic biome. countable, uncountable
"The hut's walls rose without difficulty, and everything went smoothly until the problem of the roof confronted me. Of what use the four walls without a roof? And of what could a roof be made? There were the spare oars, very true. They would serve as roof-beams; but with what was I to cover them? Moss would never do. Tundra grass was impracticable. We needed the sail for the boat, and the tarpaulin had begun to leak."
2
a vast treeless plain in the Arctic regions where the subsoil is permanently frozen wordnet
3
A long stretch of something, such as time. countable, uncountable
"His wife and he were childhood sweethearts; he had known her for 25 years. (He will call her “my wife” throughout, just as he cannot bear to name his two sons, however carefully and lovingly he will eventually describe them. They remain “the older one” and “the younger one.”) There are tundras of time for him to cross and cross again as he recalls their life together and its sudden end: a quarter‐century of quotidian love and bruises and the ultimate estrangement of long familiarity."