biv·ou·ac ( P ) Pronunciation Key (bv-k, bvwk)
n.
A temporary encampment often in an unsheltered area.

intr.v. biv·ou·acked, biv·ou·ack·ing, biv·ou·acs, also biv·ou·acks
To camp in a bivouac.

re: Did "Mr Lewis made it up using poetic licence!"

In his day, you didn't even need a camping licence to bivouac.