Various military and naval expressions made their way into our language through the long contacts in past centuries of English soldiers and sailors with Hollanders, either as their foes, fighting on Dutch soil, or as their allies.
One expression in particular became well known. It was that used by Dutch tavern keepers when the bugler or drummer sounded the nightly call for all to return to their quarters.
The tavern keepers said, “Tap toe,” meaning, “The tap (or bar) is to (or closed).” To the English soldier that sounded like tattoo.
Hence, from the cause of its utterance, the term was adopted and transferred to the signal itself.
The term tattoo as applied to patterns marking the skin, is entirely unconnected with the foregoing word. It was adapted from the Polynesian name for the practice, tatau.