Definition of "minion"

In the past two years, NASA’s Kepler Space Telescope has located nearly 3,000 exoplanet candidates ranging from sub-Earth-sized minions to gas giants that dwarf our own Jupiter.

2013 May-June, Kevin Heng, “Why Does Nature Form Exoplanets Easily?”, in American Scientist, volume 101, number 3, page 184

God's disciple and his dearest minion

1608, Josuah Sylvester, Du Bartas his divine weekes and workes

Is this the Athenian minion whom the world / Voiced so regardfully?

c. 1605–1608, William Shakespeare, “The Life of Tymon of Athens”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene iii]

Gun. My Cannons rung like Bells. Here's to my Mistress, The dainty sweet brass Minion: split their Fore-mast, She never fail'd.

1647, Francis Beaumont, Philip Massinger, The Double Marriage (play), published 1717, page 19

Of philosophers and scholars priscae sapientiae dictatores, I have already spoken in general terms, those superintendents of wit and learning, men above men, those refined men, minions of the muses.

1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps

These favours, with the commodities that follow minion Courtiers, corrupt […] his libertie, and dazle his judgement.

1603, Michel de Montaigne, translated by John Florio, The Essayes […], book 1, p.148, London: […] Val[entine] Simmes for Edward Blount […]