-άκης

Etymology
From, or &ldquo;more correct &rdquo; from -άκ(ι) < -άκ(ιν) < -άκ(ιον),  diminutive suffix (for neuters) +  suffix for masculine. 

Suffix

 * 1) Gives a diminutive form of a masculine first name:
 * 2) An ending for family names, chiefly Cretan, also of diminutive derivation (See Usage Notes)
 * 1) An ending for family names, chiefly Cretan, also of diminutive derivation (See Usage Notes)
 * 1) An ending for family names, chiefly Cretan, also of diminutive derivation (See Usage Notes)

Usage notes
Family names suffixed -άκης are attested in Byzantine times: e.g. c.1250. A systematic registering of surnames in Greece started in the 19th century. -άκης was frequent in Mani (where more often it became ) and chiefly in the island of Crete (where also the augmentative is found in contrast to the diminutive -άκης).

Which of the two alternative spellings ( or -άκης) is more correct, is still debated. Currently (2010s), some people insist on -άκις, although -άκης is much more frequent.
 * Notable -άκης: the writer Nikos Kazantzakis, the composer Mikis Theodorakis.
 * Notable -άκις: the composer Manos Hatzidakis, the father of Greek Georgios Hatzidakis.