There is a mistake in the section of "Diminutive and short forms" of "Related names". In Greek the name "Gus" (yuck!) is listed. This is a misnomer. It's in use only by Greek-Americans just for blending in. The same is the case with other names usages, like Jim for Dimitris, Bill for Vasilis (Basil). This is hideous and should be corrected.Other diminutive and short forms in Greek that are not listed are: Kosta, Kosti (Kos-TEE), Kostandi (kos-tan-DEE), Dino (DEE-no), Kostaki (Kos-TA-kee).Important note: Like another name-fellow commented, in Greek, all masculine forms of names in the subject case have an "s" in the end. So, it's: Kostas, Kostis, Kostandis, Dinos, Kostakis.
Other diminutive and short forms in Greek that are not listed are: Kosta, Kosti (Kos-TEE), Kostandi (kos-tan-DEE), Dino (DEE-no), Kostaki (Kos-TA-kee).
Important note: Like another name-fellow commented, in Greek, all masculine forms of names in the subject case have an "s" in the end. So, it's: Kostas, Kostis, Kostandis, Dinos, Kostakis.