>An authorized instructor is a CFI with the appropriate ratings..
The official definition is below. Whilst you can count your EASA training towards requirements some things ( eg endorsements etc) require an authorised instructor. Part 61.1 defines this as(i) A
person who holds a ground instructor certificate issued under
part 61 of this chapter and is in compliance with § 61.217, when conducting
ground training in accordance with the privileges and limitations of his or her ground instructor certificate;(ii) A
person who holds a flight instructor certificate issued under
part 61 of this chapter and is in compliance with § 61.197, when conducting
ground training or
flight training in accordance with the privileges and limitations of his or her flight instructor certificate; or(iii) A
person authorized by the
Administrator to provide
ground training or
flight training under part 61, 121, 135, or 142 of this chapter when conducting
ground training or
flight training in accordance with that authority.