Lewis and Short's Latin dictionary doesn't say anything about the derviation of ovatio, but says for the defective verb ovare:

[cf. Sanscr. root u-, avate, to roar; Gr. au)/w, a)vuw , to shout], to exult, rejoice.

and notes that its general use is mainly poetical, with the more specific idea of "celebrate an ovation" being used in prose.

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So, you pays your money and makes your choice.

Bingley

Bingley