A secondary unit of organisation consisting of an aggregate of monads.
A tensor of order two and rank one.
An element, atom, or radical having a valence of or combining power of two.
A chromosome structure, usually X- or V-shaped, consisting of two condensed sister chromatids joined by a centromere.
Two persons in an ongoing relationship; dyadic relationship.
A set of two elements treated as one; a pair.
The relationship or interaction itself in reference to a couple.
Any set of two different pitch classes.
A group of two or more people, machines etc. working together; close collaboration.
A method of language learning based on mutual exchange, where ideally each learner is a native speaker in the language the other person wants to learn.
A bicycle or tricycle in which two people sit one behind the other, both able to pedal but only the person in front able to steer.
A carriage pulled by two or more draught animals (generally draught horses) harnessed one behind the other, both providing the pulling power but only the animal in front able to steer.
Together; working as one.
One behind the other.