nihilum

Latin

Univerbation of ne- +‎ hīlum; both the lack of elision of the first vowel and the shortening of the second are unexpected.

nihilum n (genitive nihilī); second declension

nothing
Et possidebunt illam onocrotalus et ericius et ibis et corvus habitabunt in ea et extendetur super eam mensura ut redigatur ad nihilum et perpendiculum in desolationem
The bittern and ericius shall possess it: and the ibis and the raven shall dwell in it: and a line shall be stretched out upon it, to bring it to nothing, and a plummet, unto desolation. Isaias 34:11.
(of) no value (in the genitive singular)

The nominative/accusative singular form nihilum is far less frequent overall than the indeclinable nihil. The form nihilum occurs especially as the object of the preposition ad or in, where it has the sense "nothing(ness)", while nihil appears more often without a preposition, and tends instead to have the sense of a negative indefinite pronoun "not anything". But there are rare examples where nihilum is used without a preposition and has the sense "not anything".
The genitive nihilī is only used in Classical Latin as a genitive of value, with the sense "worthless".
The ablative form nihilō is often used as an adverb, particularly as part of the phrase nihilō minus "none the less" (also written as one word nihilōminus).
No plural forms are attested in Classical Latin. The forms nihila (nom./acc./voc.), nihilōrum (gen.), nihilīs (dat./abl.) are attested in postclassical philosophical or mathematical texts.