Definition of "Jovial"

I know the ſhape of's Legge: this is his Hand: / His Foote Mercuriall: his martiall Thigh / The brawnes of Hercules: but his Iouiall face— / Murther in heaven?

1611 April (first recorded performance), William Shakespeare, “The Tragedie of Cymbeline”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene ii], page 390, column 1

It was pointed out in chapter 3 that [C. S.] Lewis liked to regard Jupiter as his personal presiding deity, but Mercury would have been almost as apt a choice, for Lewis had been extraordinarily favoured by that Intelligence whom, in ‘The Planets,’ he calls the ‘Lord of language’: both as a speaker and as a writer Lewis was uncommonly fluent. However, despite these talents, despite the fact that he saw Mercurial as well as Jovial strains in his paternity, and despite his opinion that Mercury shared with Jupiter a special need of rehabilitation, Lewis claimed no special relationship with the planet of the second sphere. In fact, he confesses that the Mercurial essence is almost beyond his grasp: […]

2008, Michael Ward, Planet Narnia: The Seven Heavens in the Imagination of C. S. Lewis, Oxford University Press