gherkin:  Etymologically, a gherkin may be a ‘little unripe one’. The word was borrowed from an assumed early Dutch *gurkkijn, a diminutive form of gurk, which probably came from Lithuanian agurkas. This in turn goes back via Polish ogurek to medieval Greek angoúrion, which has been linked with classical Greek ágouros ‘youth’.
small cucumber used for pickling (either a small, prickly type of cucumber produced by a certain plant (Cucumis anguria), or a green or immature common cucumber), 1660s, from early modern Dutch gurken, augurken (late 16c.) "small pickled cucumber," from East Frisian augurk "cucumber," probably from a Balto-Slavic source (compare Polish ogórek "cucumber," Lithuanian agurkas, Russian oguretsŭ), possibly ultimately from Medieval Greek angourion "a kind of cucumber," which is said to be from Persian angarah [Klein, etc.], but OED seems to regard this as unlikely. A Dutch source says the Greek is from a word for "immature" and that the vegetable originated in northern India and came to Eastern Europe via the Byzantine Empire.
The Dutch suffix is perhaps the diminutive -kin, though some regard it as a plural affix, with the Dutch word mistaken for a singular in English. The -h- was added 1800s to preserve the hard "g" pronunciation.