" dimensionless "

[Noun]  | "di*men*sion" | \ də-ˈmen(t)-shən \

1: measure in one direction; specifically : one of three coordinates determining a position in space or four coordinates determining a position in space and time

2: one of a group of properties whose number is necessary and sufficient to determine uniquely each element of a system of usually mathematical entities (such as an aggregate of points in real or abstract space); also : a parameter or coordinate variable assigned to such a property

3: the number of elements in a basis of a vector space

Origin: 14th century ;

 Middle English, from Anglo-French, from Latin dimension-, dimensio, from dimetiri to measure out, from dis- + metiri to measure {mat|measure|};

[Adjective]  | "dimensionless" 

[Noun]  | "dimension"