Crossword puzzle clue "narrowing toward one end"

Narrowing toward one end

Sign of a narrowing path

Gradually narrowing waterway

Narrowing of a corporeal passage

Gets thinner toward one end

"I'm the beginning of eternity, the end of time and space, the beginning of the end, and the end of every place ..."

Work together toward a common end

Why a student might cram toward the end of the term