tactic: [17] Tactics denotes etymologically ‘arrangement, setting in order’. It goes back ultimately to Greek tássein ‘put in order’, hence ‘arrange in battle formation’. From this was derived taktós ‘arranged’, which formed the basis of the further adjective taktikós ‘concerned with arrangement or (military) planning’ (source of English tactic and tactical [16]). It was used in the plural, taktiká, for ‘matters relating to arrangement’, and this served as a model for English tactics. [tactic etymology, tactic origin, 英语词源]