What does "ad hoc" means?

[Sombat2]

I found this word in the paper I read.

"This procedure requires an ad hoc definition
of an equivalent intermolecular reference system"

What's the meaning of "ad hoc" in this sentence.

Thanks.

[Torsten]

Please read this: The usage of the word 'ad hoc'

Also, your question should read What does ad hoc mean?

TOEIC listening, photographs: A man on a ladder

[Ivo]

This procedure requires an ad hoc definition
of an equivalent intermolecular reference system"

What does ad hoc mean in the sentence above?

In my humble opinion special will fit the case.

Here are a few words concerning with the phrase in question:

ad hoc = special, arranged for this purpose , in this case

spontaneous, undigested, arbitrary, random

a coordinated policy instead of ad hoc decisions - a coordinated policy , rather than arbitrary decisions

a synonym of ad hoc makeshift = temporary replacement ; palliative

self-made; improvised

After our makeshift dinner I will treat you with a bottle of wine. - After our impromptu dinner, I'll give you a bottle of wine.

Ivo