Engine family
Engine family means a group of engine configurations that are expected to have similar emission characteristics throughout the useful lives of the engines (see 94.204), and that are (or were) covered (or requested to be covered) by a specific certificate of conformity.
Source
40 CFR § 94.2
Scoping language
The definitions of this section apply to this subpart. They also apply to all subparts of this part, except where noted otherwise.