श्री गुरुभ्यॊ नमः श्री परम गुरुभ्यॊ नमः श्री परमॆष्ठि गुरुभ्यॊ नमः

Sri Bhasakararaya in his Varivasya Rahasya 2 nd Chapter gives 15 meanings for panchadashi Mantra, that is as many meanings as the letters of the Mantra.

पुरुषार्था निच्छन्द्रिः पुरुषैरर्थाः परिज्ञेयाः
अर्थानादरभाजां नैवार्थः प्रत्युतानर्थः
एतॆनार्थज्ञानस्य नित्यत्वमुक्तं भवति

Those who are in quest of the goals of human desires, Purushaartha, shall comprehend the meaning. Those who ignore the meaning there is no attainment of their desires; on the contrary it ruins (anartha)

अथातः पूर्णगायत्र्याः प्रतिपाद्योsर्थ आदिमः
भावार्थः संप्रदायार्थॊ निगर्भार्थस्तुरीयकः

कौलिकार्थॊ रहस्यार्थॊ महातत्वार्थ एव च
नामार्थ शब्दरूपार्थश्चार्थे नामैकदॆशगः

शाक्त्यार्थः सामरयार्थः समस्तसगुणार्थकौ
महावाक्यार्थ इत्यार्थाः पञ्चादश्याः स्वसंमिताः

For this reason, hence forth it is dealt with, firstly the true significance of the whole of the Gayatri, then Bhavartha, Sampradaayaartha, fourthy Nigarbhartha Kaulikaartha, Rahasyaartha, Mahatatvaartha, Naamaartha, Shabdharoopaartha, NaamaikaDeSartha, Saktaartha, saamarasyaartha, samastaartha, sagunaartha, and Mahavakyaartha, that is, as many meanings, Artha as there are letters in panchadashi Mantra.

As it is time consuming to provide the original Sanskrit slokas, I am giving the English meaning of the verses.

First is Gayatri meaning in Panchadashi Mantra:–

The letter “ka” signifies Kameswara, that is He who desires, by virtue of which it stands for Brahman; that signifies ‘Tat’ in the Gayatri. The second letter “E’ stands for ‘Kameswari’ that is savitur varenyam. “ee’ stands for “bhargo devasya dhi” means the Siva who is immanent and all sustaining. “la” signifies the earth ‘mahi’

HREEM maya bija signifies third and fourth pada of Gayatri.

Ha sa ka together indicate tat savitur varenyam. The next Ha indicates bhargo devasya dhi. Sa ka of the third group of panchadashi also indicate same tat savitur Varenyam and bhargo devasya dhi.

The remaining letters of the second and third group ( KOOTA) of Panchadashi are also construed as aforesaid.

Sri Bhaskararaya further says

गायत्र्यर्थस्त्रिपुरोपनिषदि कथितस्तथैव भगवते

The meaning of Gayatri of the vidya has been expounded in Tripuropanishad as well in the Devi Bhagavata.

7 meanings of Sri vidya panchadasi Mantra links:

1st meaning – Gayathri

2nd meaning – Bhavartha

3rd meaning – Sampradayartha

4th meaning – Nigarbha artha

5th meaning – Kaulikartha

6th meaning – Sarva Rahasyartha

7th meaning – Mahatatvartha

LOKA SAMASTA SUKHINO BHAVANTU SAMASTA SANMANGALANI BHAVANTU