Noun

(en noun)

valley

* 1794, , lines 49-50

To this day they dwell

In a lonely dell .

* Tickell

In dells and dales, concealed from human sight.

(obsolete) A young woman; a wench.

* Ben Jonson

Sweet doxies and dells .

Noun

The playing of a game or games, including but not limited to video games and games of chance.

* (Philip Schaff)

*{{quote-magazine, date=2013-06-28, author=(Tom Vanderbilt)

, volume=189, issue=3, page=29, magazine=(The Guardian Weekly) , title= The lose-lose logic of the machine zone , passage=The US gaming industry, in a pamphlet called Demystifying Slot Machines […], argues that "slot manufacturers need to build devices for a society with a decreasing attention span and an increasing demand for exciting, fast-paced entertainment, all in a marketplace overflowing with competing entertainment options".}}

Careful, strategic use of rules to achieve one's purposes, as one would use the rules of a game.