English

Verb

thunk

1. (humorous, nonstandard) past participle of think
   • 1939, Harold Arlen (music) and E.Y. Harburg (lyrics) (music), “If I Only Had a Brain”, performed by Ray Bolger as the Scarecrow, from The Wizard of Oz:

     I could think of things I never thunk before ...

   Who would have thunk those guys would have a problem with a little lie?

Derived terms

• who'd have thunk it

Etymology 2

Onomatopoeic

Interjection

thunk

1. Representing the dull sound of the impact of a heavy object striking another and coming to an immediate standstill, with neither object being broken by the impact.

Verb

thunk ‎(third-person singular simple present thunks, present participle thunking, simple past and past participle thunked)

1. To strike against something, without breakage, making a "thunk" sound.

   I was thunked on the head by his stick.

Etymology 3

Said by the inventors to be from the irregular jocular past tense of think, being coined when they realised that the type of an argument in ALGOL 60 could be predetermined at compile time (with a little compile-time "thought").^[1] Sometimes incorrectly claimed to be from the interjection, from the supposed sound made by data hitting the stack or an accumulator.

Noun

thunk ‎(plural thunks)

1. (computing, functional programming) A delayed computation.
   • 2009, Bryan O'Sullivan, John Goerzen, Donald Bruce Stewart, Real World Haskell, O'Reilly, page 97,

     Not surprisingly, a thunk is more expensive to store than a single number […] .

2. (computing) In the Scheme programming language, a function or procedure taking no arguments.
3. (computing) A mapping of machine data from one system-specific form to another, usually for compatibility reasons, such as from 16-bit addresses to 32-bit to allow a 16-bit program to run on a 32-bit operating system.
   • 1995 October 10, PC Mag, Volume 14, Number 17, page 326,

     If the provider of these DLLs has not updated the code to a 32-bit environment, you will have to switch to a new 32-bit library or write thunks between your 32-bit code and the 16-bit DLL.

Related terms

• thunking (noun)

Verb

thunk ‎(third-person singular simple present thunks, present participle thunking, simple past and past participle thunked)

1. (computing, functional programming, transitive) To delay (a computation).
   • 2009, Bryan O'Sullivan, John Goerzen, Donald Bruce Stewart, Real World Haskell, O'Reilly, page 97,

     Not surprisingly, a thunk is more expensive to store than a single number, and the more complex the thunked expression, the more space it needs. For something cheap such as arithmetic, thunking an expression is more computationally expensive than calculating it immediately.

2. (computing, transitive) To map (machine data) from one system-specific form to another.
   • 1995 May 16, Andrew Schulman, DOS is Dead? Look Again, PC Mag, Volume 14, Number 9, page 150,

     This efficiency is offset by the fact that some of the calls made by Win32 apps must now be thunked down to 16 bits, something that isn't necessary in Windows NT and OS/2.

See also

• closure

References

1. ↑ thunk, entry in Free On-line Dictionary of Computing.