On 23 January 2016 at 08:36, Krishnaprasad G <krishnaprasadah.g@gmail.com> wrote:

Dear Martin Gansten
This probably means
Vyakarana Mahabhasya which is written by Patanjali.
He is believed to be an incarnation of Shesharaj who is a bed of Lord Vishnu. So Ahi means Snake. Gavi means his speech or Vanee. In Sanskrit gow means cow and also speech. Here in this context the meaning is to be considered as speech and derivative of the same would lead to this new word.
This is used by famous commentator Mallinatha in his Raghuvamsa etc at the commencement of the same.

That is correct, however there is no word called gavī. Monier Williams lists the word and even gives the citation Śiśupālavadha 2.68 but he (or the Pandit he relied on) have clearly erred as Śiśupālavadha 2.68 has the samasta form śeṣagavī. The form gavī derives from the affix ṭac at the end of a tatpuruṣa compound by the rule gorataddhitaluki (5.4.92) followed by eco’yavāyāvaḥ (6.1.78) and then and then ṅīp by the rule ṭiḍḍhāṇañdvayasajdaghnañmātractayapṭhakṭhañkañkvarapaḥ (6.4.148). Hence aheḥ gauḥ ahigavī. 

अहेः गौः इति अहिगवी। ‘अहिगो’ इति समासात् ‘गोरतद्धितलुकि’ (पा॰सू॰ ५.४.९२) इत्यनेन समासान्ते टच्प्रत्यये ‘एचोऽयवायावः’ (पा॰सू॰ ६.१.७८) इत्यनेनावादेशे ‘टिड्ढाणञ्द्वयसज्दघ्नञ्मात्रच्तयप्ठक्ठञ्कञ्क्वरपः’ (पा॰सू॰ ४.१.१५) इत्यनेन ङीपि ‘यस्येति च’ (पा॰सू॰ ६.४.१४८) इति भलोपे ‘अहिगवी’ इति प्रातिपदिकं सिद्धम्।

Mallinātha calls the Mahābhāṣya pannagavī. This and other references to Patañjali as Śeṣa one may refer the Prastāvanā of Adhyātmarāmāyaṇe'pāṇinīyaprayogāṇāṃ Vimarśaḥ. The relevant pages are attached.