fine distinction

At first sight it may seem rather a fine distinction to separate torrents from rivers by the presence or absence of terraces.

He knew the fine distinction between drama and tragedy, the tragedy which nature prevails upon the sensitive to accept.

Miss O'Malley acted a difficult, almost an impossibly difficult, part with a fine distinction.

"He said it had him robbed," said Father McCormack, with the air of a man who is carefully making a fine distinction.

When they passed its threshold the fine distinction of rank ceased.