Does writ petition amounts to legal suit

No, a Writ Petiton is not a Suit; a Writ Petiton is a Constitutional remedy as against a Suit which is a statutory remedy under applicable civil laws. Strictly speaking, authorisation to institute a Suit cannot be extended to mean authorisation for the purposes of a Writ Petition or vice versa, though, frankly speaking most authorisations that I have come across confer a wide authorisation specifically authorising Suits, Writs, Abitrations, Applications etc. etc. kind of omnibus; such authorisation is of course valid, unless specifically stated otherwise in the Articles of Association of the Company.

The question is akin to "Power of attorney". Is it possible in Writ or not? 

Details above are ambiguous please.

The diffrence of writ and suit has been explained above. Bombay ahigh acourt has pecuniry jurisdiction in civil matters also. So if it is a suit write suit do not mention writ if it is a writ write writ

That is to say:    "Retain all the content as it is. But the title word need be Suit / Writ as per the case."

U can give the resolution in the below mentioned manner in which all the things related to legal matter is covered :

“RESOLVED THAT in addition to earlier authorities given in this regard Mr. _______________, Authorized signatory  of the Company be and is hereby severally authorized to sign, execute and file complaint, petition, suit, appeal, writ petition, Caveat, statements, execute vakalatnama, defend any legal action, sign and file rejoinder/reply, affidavit, appear and depose before Supreme Court, competent High Courts of India, District Court and appear before any Civil & Criminal Court of law or tribunal, in any of the matters for or/and against the Company to perform all such acts and deeds as may be necessary in this regard and all other matters arising from any legal  proceeding and to represent on behalf of the Company.”

In 'Suit'     (May pl. be corrected if the understanding is wrong).

So, as of querry:    YES, writ petition amounts to legal suit with above

The paragraph below is one of the possibilities listed on a worthy website in the cotext of: "What happens after a Writ is filed in the Registry".

"The Court may dismiss the Writ Petition and ask the Petitioner to file Suit or adopt appropriate legal recourse as available to him; or where the Petition involves disputed question of facts, which cannot be ascertained unless evidences are led by both the parties, the Court may direct the Petitioner to file Suit or adopt appropriate legal recourse as available to him". 

This does not mesh with the understanding in the earlier posts on this thread.

Next, If the Writ is not admitted, then what is above all about?