the.com/weatherstripping
The thin foam frontier where your house wages quiet war on the wind.
means Strips of foam, rubber, or felt sealing gaps around doors and windows to block drafts and save heat.
from From weather (the elements outside) plus stripping (narrow strips applied) — a plain industrial-age coinage for a plainly useful job, dating to the early 1900s.
Real savingsSealing leaks can cut heating bills measurably.
Many formsFelt, foam, vinyl, rubber, even spring metal.
Door bottomThat sweeping strip is called a door sweep.