It means: The filling (as in the filling for a food).
Granulated Cement Filling
Sponge cake with cream filling
Key/code
it has lots of holes which need filling... if you know what i mean
It's a pump for filling something with air.
It means there is a leak that needs repaired.
Filling out form is answering a sheet of paper that contains the questions to answer who you are and where you are
when you dont want something open you fill it in
Iron filling is a filling which can be made by iron filling
Yes, If you mean by a Earth Retaining Structure.
DIY means "do it yourself."