a large, fish-eating mammal that has very thick fur and lives in the sea:

an official mark on a document which shows that it is legal or actually what it claims to be:

A seal of approval means that something has been proven to be good or is very pleasing:

anything that prevents the escape of liquid or gas from a container or pipe:

to close a container or opening, or to prevent the escape of a liquid or gas from something:

If official documents are sealed, they cannot be seen or are not available to the public.

to formally approve an agreement:

an official mark on a document, sometimes made with wax, that shows that it is legal or has been officially approved:

a thin piece of paper or plastic that covers the opening of a container and has to be broken before the contents can be used:

something fixed around the edge of an opening to prevent liquid or gas flowing through it:

to make an agreement more certain or to approve it formally:

to close an entrance or container so that nothing can enter or leave it:

to cover a surface with a special liquid in order to protect it:

to close a letter or parcel by sticking the edges together: