Definition of "overhead" I am writing a paper on the invariance thesis introduced by Cees F. Slot and Peter van Emde Boas as;


  'Reasonable' machines can simulate each other within a polynomially bounded overhead in time and a constant-factor overhead in space.


The paper I am writing is in Croatian where I cannot find a properly convenient word like "overhead". Also, I am unable to find a strict Computer Science definition for the term.

Specifically, I have $Time(M)$ as the cost of reducing the $\lambda$-term $M$ to its normal form and a Turing machine able to simulate this reduction in $O((Time(M))^4)$. Therefore, I would like to say  "this TM can simulate $\lambda$-calculus with polynomial-time [overhead]" concisely as it is in English.

I would appreciate any suggestion in the form of literature references for the definition, advice on how to best define it myself or even synonyms of the word.
I doubt that “overhead” is a term. Here’s what we use in Russian papers:


оверхед — direct transliteration (for informal texts)
издержки — costs (of production)
Translations of “slowdown” (for time) and “blow-up” (for space).