In each of the sentences below, a writer has referenced a person, place, or thing with an appositive, a word or phrase equivalent to another word or phrase, but erroneous punctuation or syntax introduces a flaw in sentence construction. The discussion following each example explains the problem, and a revision illustrates its resolution.
1. A dome-shaped structure made of ice or snow, or igloo, is a form of temporary shelter.
When a term is defined, the definition should follow the term—the focus of the sentence—rather than serve as an introduction to the concept followed by the term: “An igloo, or dome-shaped structure made of ice or snow, is a form of temporary shelter.”
2. The first of two main strategies when building application security is the top-down or proactive approach.
The strategy is not called “the top-down or proactive approach”; it is called “the top-down approach” or “the proactive approach.” To clarify that these names are alternatives to each other, rather than elements of a compound name, the second adjective should be treated as a parenthetical: “The first of two main strategies when building application security is the proactive, or top-down, approach.”
3. FBI Criminal Investigation Division Deputy Assistant Director John Smith discussed the report.
Technically, this sentence begins with a job title—a cumbersome one, at that—rather than an appositive, which is similar in function but not in form. With some reconstruction of elements, the title is easily converted to an appositive, but note that when a title is treated this way, it is no longer capitalized (though the associated proper nouns are): “John Smith, deputy assistant director of the FBI’s Criminal Investigation Division, discussed the report.”
4. The group, OurMine, took responsibility for the hacks after the tweets were deleted.
Assuming that no previous reference has been made to the organization in question (whether identified by the word group or a synonym), its name is an essential component of the sentence and should not be set off as a discretionary parenthetical: “The group OurMine took responsibility for the hacks after the tweets were deleted.” (If it had been previously mentioned, then group would be an appositive of “OurMine,” and the original sentence would be correct.)
5. The outcome depends on the quality of the plans developed during the previous, inspection phase.
Here, two aspects are being ascribed to the phase—it is previous to another phase, and it involves inspection. However, the two aspects are not equivalent, so they should not be treated as coordinate adjectives: “The outcome depends on the quality of the plans developed during the previous phase, inspection.” (Or “The outcome depends on the quality of the plans developed during inspection, the previous phase.”)