What are homographs?

Which word can mean:
sides of a river OR
a place to keep your money?

Which word can mean:
paper money OR
a musical sound?

Which word can mean:
a green area OR
leaving a car somewhere?

Which word can mean:
to reserve a place OR
something with pages?

Which word can mean:
coins OR
to alter something?

Which word can mean:
something that can cut trees OR
observed?

Which word can mean:
a water outlet OR
to knock lightly?

Which word can mean:
a way to score points in rugby OR
make an effort?

Which word can mean:
an instrument that tells the time OR
looking at something?

Which word can mean:
a sound a dog makes OR
the outer layer of a tree?