I am working on my Bachelor thesis and I need to use the formal way of saying 'under the hood'. The context is similar to: The agent accepts the message, performs processing and relays it to DUA. Under the hood, it is done (achieved) by...

Or is that phrase 'under the hood' already appropriate for using in that formal writing? Thank you in advance

  • 1
    "Under the hood" isn't exactly formal but it's not so crude that anyone would really object to its use in a technical document. Commented Dec 12, 2021 at 13:45
  • "By Sir Robin".
    – Hot Licks
    Commented Dec 12, 2021 at 15:10
  • The term 'deep structure' has been freed from the confines of transformational grammar, but may not be idiomatic enough in general use for your purposes. Commented Dec 12, 2021 at 17:36
  • This is not a synonym, but it is formal: Programmatically, it is achieved by . . . Commented Dec 12, 2021 at 18:35

5 Answers 5



While this is still figurative (in that a software mechanism does not have a literal inside), it is perhaps more formal than under the hood.

Internally, it is done by ...

(Hat tip to Mick's comment.)


This is implemented by ...

Implementation involves ...

To implement this, ...

Per Wikipedia

In computer science, an implementation is a realization of a technical specification or algorithm as a program, software component, or other computer system through computer programming and deployment. Many implementations may exist for a given specification or standard.

In computer science (apparently the general field you're writing in), it's not just the algorithm or specs that are interesting. The way an algorithm is implemented is important too.

"Implement" is kind of a traditional word in such a context.


A perhaps slightly more formal (but still figurative) alternative is

Behind the scenes it is done (achieved) by...

behind the scenes

Revealing or reporting the hidden workings

a behind-the-scenes account

a behind-the-scenes glimpse m-w

Figurative. Out of attention or consideration. OED

under the hood

Mainly American

Something that is under the hood is not immediately visible or obvious.

When you check under the hood, we are using a lot of energy.

The new version of the application has been updated with lots of under the hood fixes. Macmillian

The NGram shows that under the hood is much less common. Several online dictionaries don't include it.

Messages are sent and received using the Pipe Service and routed using the Endpoint Service. Typically, applications interface with the Pipe Service directly and the routing is hidden behind the scenes. I. Taylor and A. Harrison; From P2P and Grids to Services on the Web:

The debug messages tell us what STP on SW3 is thinking behind the scenes, with timestamps. Wendell Odom; Cisco CCNA Routing and Switching ICND 200-101

In Google Books under the hood appears in the titles of a few technical books, but I'm not finding it in the text itself:

Anthony J. Dos Reis; C and C++ Under the Hood

Kirk McElhearn; The Mac OS X Command Line: Unix Under the Hood

As far as connotations, under the hood for me is more static (conveying what's there), behind the scenes more dynamic (conveying what's going on.)

  • Is this really more formal?
    – Laurel
    Commented Dec 12, 2021 at 13:56
  • @Laurel I've added an opinion and NGram--thanks.
    – DjinTonic
    Commented Dec 12, 2021 at 13:58

Unobserved might be another candidate...

"... what is going on unobserved is actually rather fascinating, involving several species of mollusc acting collaboratively... ".

... a lot depends on the context, about which you say nothing.

  • In order to make this an answer, rather than a comment, could you please expand upon "unobserved by reference to some authority?
    – Greybeard
    Commented Dec 12, 2021 at 20:03
  • No, it's definitely an answer... otherwise you would have seen it's a comment. Please don't tell other people how to answer a question, thanks. Commented Dec 12, 2021 at 22:05

It is the case that what is “under the hood” is not immediately obvious. However, it does not mean doing something sub rosa, in secret, or even without observation.

It is metaphorically used to express getting into the details, getting to understand how something really works.

The vast majority of NGram entries are literal, relating to automobiles. (Beware the Hood Act, and what is and is not required under the Hood Act, for false positives.j

Ross Perot in his 1992 presidential campaign vowed to “get under the hood” of the American economy:

Perot’s brand of plainspoken populism—he vowed to “get under the hood” and fix the American economy.

(From an article in The Atlantic.)

Around the turn of the century, the metaphorical use was often applied to the internal workings of computer programming and computer operating systems.

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