Noun

(en-noun)

The basic, central, or essential point or feature.

The crux of her argument was that the roadways needed repair before anything else could be accomplished.

The critical or transitional moment or issue, a turning point.

* 1993 , Laurence M. Porter, "Real Dreams, Literary Dreams, and the Fantastic in Literature", pages 32-47 in'' Carol Schreier Rupprecht (ed.) ''The Dream and the Text: Essays on Literature and Language .

The mad certitude of the ogre, Abel Tiffauges, that he stands at the crux of history and that he will be able to raise Prussia "to a higher power" (p. 180), contrasts sharply with the anxiety and doubt attendant upon most modern literary dreams.

A puzzle or difficulty.

The perpetual crux of New Testament chronologists. — Strauss.

The hardest point of a climb.

* 1973 , Pat Armstrong, "Klondike Fever: Seventy Years Too Late", in Backpacker , Autumn 1973, page 84:

The final half-mile was the crux of the climb.

* 2004 , Craig Luebben, Rock Climbing: Mastering Basic Skills , The Mountaineers Books, ISBN 9780898867435, page 179:

Most pitches have a distinct crux', or tough spot; some have multiple '''cruxes'''. ¶ Climb efficiently on the "cruiser" sections to stay fresh for the ' cruxes .

* 2009 , R. J. Secor, The High Sierra: Peaks, Passes, and Trails , Third Edition, The Mountaineers Books, ISBN 9780898869712, page 51:

Continue climbing the groove; the crux is passing some vegetation on the second pitch.

(heraldiccharge) A cross on a coat of arms.

Noun

(label) Endlessness, unlimitedness, absence of end or limit.

A number that has an infinite numerical value that cannot be counted.

* {{quote-magazine, date=2012-01

, author=Michael Riordan , title=Tackling Infinity , volume=100, issue=1, page=86 , magazine= citation , passage=Some of the most beautiful and thus appealing physical theories, including quantum electrodynamics and quantum gravity, have been dogged for decades by infinities' that erupt when theorists try to prod their calculations into new domains. Getting rid of these nagging ' infinities has probably occupied far more effort than was spent in originating the theories.}}

An idealised point which is said to be approached by sequences of values whose magnitudes increase without bound.

(label) A number which is very large compared to some characteristic number. For example, in optics, an object which is much further away than the focal length of a lens is said to be "at infinity", as the distance of the image from the lens varies very little as the distance increases further.

(label) The symbol .