Hungarian Historical Phonology záp
záp 'Leitersprosse; ein Brett der Wagenwand od. der Trage'
First attestation/Old Hungarian data
[coming]
Important dialectal forms
[coming]
Uralic/Ugric/Pre-Hungarian reconstruction
(Disputed:)
UEW: PUg *sappɜ 'post, stake, bar; Pfahl, Stange'
Loan etymology
None suggested
Cognates suggested in earlier research
UEW:
Mansi: South (TJ) šapə·l 'Pfahl, Stange', (KO) sōpəl 'Pfahl, Stange, Baumstumpf', (KU) sopəl: s̀ētsopəl 'Zaunpfahl, -stange', West (P) šoplə 'Pfahl, Stange', North (So) sopla: āvisopla 'Türpfosten'
Commentary
Both UEW and EWUng doubt the etymology due to the clearly irregular z in Hungarian. EWUng also notes that the Hungarian word is first attested in the late 18th century. It should be added that the origin of Mansi *š is also unclear in this etymology. It is possible that the Hungarian and Mansi words show only accidental similarity.
Conclusion
The Ugric etymology is very unlikely.
References
EWUng 1660, s.v. záp: ? Proto-Ugric
UEW s.v. sappɜ: ? Proto-Ugric Uralonet