Words

Akkadian
peṣû - white (CAD P 328, AHw. 857)
Derived words: pūṣāwūtu ‘laundry work’ (CAD P 538, AHw. 883); pūṣāyu ‘launderer’ (CAD P 538, AHw. 883); puṣāˀū (puṣû) ‘white’ (CAD P 328, AHw. 857); puṣīˀū, puṣû ‘white gold’ (CAD P 539, AHw. 883); puṣṣû ‘white’ (CAD P 539); pūṣu ‘white spot’ (CAD P 539, AHw. 883).
May be related to PCS *pṣḥ ‘to be bright’.
Akkadian
pētḫallu - riding horse (CAD P 335, AHw. 858)
Obviously a composite word comprising the G participle from petû ‘to open’ and ḫallu ‘crotch, region between the thighs; the hind legs of animals’ (CAD Ḫ 45).
Akkadian
petû - to open (CAD P 340, AHw. 858)
Var. patāʾu, patû.
Derived words: mupettītu ‘opener’ (AHw. 674, CDA 217); mupettû ‘(a person) opening a sluice-gate’ (CAD M₂ 210, AHw. 674); naptētu ‘key’ (CAD N₁ 324, AHw. 742); naptû (neptû) ‘key’ (CAD N₁ 324, AHw. 742); neptû ‘opening, breach’ (CAD N₂ 171, AHw. 779); pattû ‘informed’ (CAD P 546); pattūtu ‘open chariot’ (CAD P 286, AHw. 849); pētânu ‘opener’ (AHw. 858); petîš ‘openly’ (CAD P 337, AHw. 858); petītu (patītu) ‘opened, mated’ (CAD P 337); pētû ‘opener’ (CAD P 357, AHw. 861); petû (patû, patiˀu, patˀu) ‘open’ (adj.) (CAD P 338, AHw. 858); petûtu (or pētûtu) ‘revelation’ (CAD P 358, AHw. 861), pītu (a musical term) (CAD P 447, AHw. 871); pītu (pitû) ‘opening’ (CAD P 445, AHw. 871); šaptû ‘opened up’ (CDA 358); taptû ‘opened up’ (CAD T 196, AHw. 1323); teptītu (teptētu, taptītu, taptētu) ‘opening up (land for cultivation)’ (CAD T 346, AHw. 1347).
Akkadian
piāḳu - to (be) narrow (CAD P 141, AHw. 861)
Var. pâḳu.
Adjective: pāḳu, pīḳu. Derived words: pīḳu ‘distress, difficulty’ (CAD P 394); pūqu, puqqu (a body part?) (CAD P 514, AHw. 880).
Cf. Arb. fwq (VII) ‘to become lean, emaciated’, (VIII) ‘to become poor, in want or need’, fāqat- ‘poverty, want or need’ (Lane 2461f.), cf. especially pīḳu ‘distress, difficulty’.
Akkadian
piˀāḳu - to be tight (CAD P 141, AHw. 861)

Var.: pâḳu, pêḳu. 

Akkadian
pidakku - (a building) (CAD P 434, AHw. 869)
No etymology can be suggested.
Akkadian
pīdānu - assaying(?) (CAD P 358, AHw. 861)
Or pidānu, var. pādunu.
Von Soden’s comparison with Arb. ftn ‘to test, to try’, Gez. fatana ‘to try, to test, to investigate’ (CDG 170) has been recently defended in Kleber 2016:130f., who does not discuss (nor even mention) the obvious phonological discrepancy (d in Akkadian vs. t in Arabic).
Akkadian
pidarānu - (mng. uncert.) (CAD P 359, AHw. 862)
Or piṭarānu. No etymology can be suggested.
Akkadian
pīḫātu - (a textile) (CAD P 369, AHw. 862)
No etymology can be suggested.
Akkadian
pīḫatu, pāḫatu - post, office; responsibility; province, district (CAD P 360, AHw. 862)

Related and derived words: pāḫānu ‘responsibility’ (SAD I); pāḫatūtu ‘governorship’ (CAD P 369, AHw. 862).
Usually (AHw. 862, CAD P 360) thought to be related to puḫḫu ‘to exchange’.

A source of borrowing for the Off.Arm. pḥt, Bib.Arm. päḥā and Heb. päḥā.