plural of town twinning

A complication of disproportionate blood supply between unborn twins, resulting in high morbidity and mortality.

(baseball, slang) A double play.

(crystallography) either of two separate crystals that share crystal lattice points in a symmetrical manner and intergrow

(of an aircraft) powered by two engines, one in each wing

(slang) Siblings born within twelve months of each other. / Used other than figuratively or idiomatically: see Catholic, twin.

The two main buildings of the World Trade Center, destroyed in terrorist attacks on 9/11, 2001.

Being the size of a twin bed.

Either of a pair of matching single beds. / (US) A single bed.

(idiomatic) A duplicate or counterpart that acts in a contrary, nefarious, or insidious manner.