Definition of unit of electric current

[Quantumkid]

The ampere is that constant current which , if maintained in two straight parallel
conductors of infinite length, of negligible
circular cross-section, and placed 1 metre apart in vacuum, would produce between
these conductors a force equal to 2 × 10 ^{–7} Newton per metre of length.

What is meant by orange colored text??

 

[mgb_phys]

Yes - and your question is ?

 

[DrDu]

It means that one considers the limit that the wires are infinitely thin.