Unfortunately there is no single standard definition of a simple Lie group.

There's not a single clear definition for the future of Kosovo.

There is no single fixed global definition of the term.

As usual, I don't think they will reach a single definition right there.

There is no single definition of what constitutes an ecosystem.

There is no single specific definition of which countries are middle powers.

There is no single or widely used definition of children's literature.

There is clearly no single accepted definition of the term.

We talk about democracy promotion but there is no single European definition of it.

I do not believe either that there should be a single definition of social housing.