Narrow inlet hugely useful in constructing crosswords

This time we are looking on the crossword clue for: Narrow inlet hugely useful in constructing crosswords.
it’s A 53 letters crossword puzzle definition. See the possibilities below.

Did you find what you needed?
We hope you did!. If you are still unsure with some definitions, don’t hesitate to search them here with our crossword solver.

Possible Answers: RIA.