Proto-Indo-European *steig- "to stick" became Proto-Germanic *stikkēn "to be stuck" (AHD) and Old Low German stekan. This was borrowed into Old French as estiquer "to stick, fix", becoming estiquette then etiquet, borrowed into English as ticket. The French word was for ‘a little note, breuiate, bill, or ticket; especially such a one, as is stucke vp on the gate of a Court, signifying the seisure &c of an inheritance by order of iustice’ (Cotgrave).
The same Old French estiquette is also the source of English etiquette, which was first used to mean "The prescribed ceremonial of a court; the formalities required by usage in diplomatic intercourse." The semantic shift from "ticket, label" to "prescribed routine" presents no difficulty, the OED tells us.
In Greek the suffixed from *stig-yo- became στίζω stizō "to prick, puncture", and στίγμα stigma "mark".
*steig- is also found in raita and possibly tiger.