What is "collocations"

Usage examples of "collocations".

The slow passing out of existence of those collocations of stars which for thousands of years have formed famous ``constellations,'' preserving the memory of mythological heroes and heroines, and perhaps of otherwise unrecorded history.

But I know one thing: anyone leafing through the catalogue of books will often find, among the collocations that only the librarian understands, one that says ‘Africa,’ and I have even found one that said ‘finis Africae,’ the end of Africa.