Probably identical toهَمّ(hamm,“concern”) from the rootه م م(h m m), with sound changes typical to Arabic, as e.g. inإن(ʔin). Note also the nounهَن(han,“thing; self,synonym ofنَفْس(nafs)”), often mentioned in grammars as one of“the six nouns” also known as “five nouns“, which became obsolete due to often referring to genitalia.
And the Companions of the Garden shall cry out to the Companions of the Fire[literally "that"] "We have found true what our Lord promised us. So did ye find true what your Lord promised you?" They shall say, "Yes", then an announcer shall announce between them[literally "that"] "God's curse is on the evildoers!"
And (remember) when your Lord brought forth from the Children of Adam, from their loins, their seed (or from Adam's loin his offspring) and made them testify as to themselves (saying): "Am I not your Lord?" They said: "Yes! We testify,"lest you should say on the Day of Resurrection: "Verily, we have been unaware of this."
In sense 1.2, ifأَنْ(ʔan) and the clause it introduces pertain to a verb, then they are syntactically itssubject. However, this clause is never allowed to precede the verb: Arabic does not accept the phrasing*أَنْ قُلْتُ لَكَ ذٰلِكَ سَبَقَ(*ʔan qultu laka ḏālika sabaqa, literally“that I told you so has passed”).
If the verb phrase inside the clause is relatively short, this can serve to distinguish anأَنْ-phrase from the equivalent verbal noun. A sentence likeسَبَقَأَنْ تَعَامَلْنَا(sabaqaʔan taʕāmalnā,“we have already done business together”) is perfectly fine being reworded toتَعَامُلُنَا سَبَقَ(taʕāmulunā sabaqa) instead ofسَبَقَ تَعَامُلُنَا(sabaqa taʕāmulunā), but*أَنْ تَعَامَلْنَا سَبَقَ(*ʔan taʕāmalnā sabaqa) is ungrammatical.
Notice that sense 1 is twice shown introducing the complement of prepositions likeقَبْلَ(qabla,“before”) andبَعْدَ(baʕda,“after”); this also includes phrasal ones likeبِمُجَرَّدِ(bi-mujarradi,“as soon as”,بِـ(bi-,“with”) +مُجَرَّد(mujarrad,“merely”)). If this preposition is in a past context, then the verb inside the clause can in fact be either pastor nonpast: the overall meaning will be past-tense either way. Compare the example above that translates to "the people elected...", which shows the use of a past-tense verb withبَعْدَ أَن(baʕda ʔan), to the following:
مَرِضَ قَبْلَأَنْ يُسَافِرَ
mariḍa qablaʔan yusāfira
He fell sick before he traveled.
(literally, “he fell sick before[that] he travel”)
If pertaining to a verb,أَنَّ(ʔanna) and the clause it introduces are syntactically itsobject. This distinguishesأَنَّ(ʔanna) fromأَنْ(ʔan), especially in the case outlined in the usage note above.
أَنَّ(ʔanna) must be followed immediately by the subject of the clause it introduces, in the accusative case. An attached object pronoun can satisfy this condition.
The sole exception is in the relevant sense ofأَنْ(ʔan) above. In that case, such a subjectcan appear and cause theأَنَّ(ʔanna) pronunciation to resurface, but it is only optional. Compare the following alternative phrasing:
From the rootء ن ن(ʔ n n), probably also related to the rootه م م(h m m) connected to the idea of worry, affect. Compareهَنَاة(hanāh,“misfortune, accident”).
Tropper, Josef (2003), “Sekundäres wortanlautendes Alif im Arabischen”, in Kogan, Leonid, editor,Studia Semitica (Orientalia: Papers of the Oriental Institute; III), Moscow,→ISBN, pages207–209