bank up

Verb

bank up (third-person singular simple present banks up, present participle banking up, simple past and past participle banked up)

1. To press a mound of something against something else.
2. To make a mound to guard against something.
3. (intransitive) To bank (form a bank; gather in masses).
   • Next, heavy soft clouds, banking up till the sky becomes overcast, are recorded, easily recognised by their lowering appearance, due to the dampness of the air, which also causes them to reflect the glare of large fires or the lights of cities[…]1893, Henry Newton Dickson, Meteorology: The Elements of Weather and Climate, page 10
   • Then turning: "There'll be more rain," he said, "you can see the clouds banking up to the North-West, larger than these."1920, Elliot Lovegood Grant Watson, Deliverance, page 143

   Synonyms:

   fortify