support oneself; "he could barely exist on such a low wage"; "Can you live on $2000 a month in New York City?"; "Many people in the world have to subsist on $1 a day"
under or below an object or a surface; at a lower place or level; directly beneath; "we could see the original painting underneath"; "a house with a good foundation underneath"
on the lower or downward side; on the underside of; "a chest of drawers all scratched underneath"