(computing) An extension to the x86 CPU instruction set architecture, providing direct hardware support for advanced floating-point arithmetic operations (rather than requiring them to be emulated in software).

Synonym of Turner syndrome

(pharmacology) Used to form names of blood coagulation factor Xa inhibitors used as antithrombotics.

(biology) The system that determines the sex of offspring among grasshoppers, crickets, cockroaches, and some other insects, in which females have two sex cells (XX) and males have only one sex cell (X0, or simply X; the 0 signifies the lack of another X).

to stay away from; to alienate