x factor

plural x factors

1. alternativeAlternative spelling of X factor.

plural X factors · alternative x-factor · alternative x factor

1. idiomaticAn unknown or hard-to-define influence; a factor with unknown or unforeseeable consequences.

   We slid into our office, past two women discussing the "X factor," an apparently undefined quality their firm felt they lacked.

   1992, Lia Matera, Prior Convictions, page 121

   3 more examples

   The map can be misleading. It can appear to contain all the relevant information, but in real life, there is always an X factor.

   1999, Joel R. DeLuca, Political Savvy: Systematic Approaches to Leadership Behind the Scenes, page 75

   And put him on an LA film set and he glowed with that indefinable X-factor that agents the world over wished they could bottle.

   2007, Tasmina Perry, Daddy's Girls, page 12

   Whether it's trade, global warming, Darfur or North Korea, China has become the new x factor, without which no durable solution is possible.

   2007 December 31, Fareed Zakaria, “The Rise of a Fierce Fragile Superpower”, in Newsweek, page 38

2. idiomaticA special talent, ability or quality or its indefinable cause.
3. Prothrombinase.

   Synonyms: factor X

4. astrophysicsThe proportionality constant which converts CO emission line brightness to molecular hydrogen mass.