What was the word tattoo first used for?

Most historians believe the Word tattoo comes from the south seas island people's Word 'tatau', which means literally to 'tap repeatedly', from their method of tapping in the ink in the tattoo motifs that decorated their bodies...
The electric machine as we know it did not come into being until 1925, before that all tattoos were hand picked, or tapped in. Since then with high tech improvements it has gotten where there are very few people who still hand tap tattoos in the original south seas fashion. Hope this helps.