The skin-design word tattoo comes from Tahitian tatau. The identically spelled military signal has a separate history through Dutch. Distinguishing the senses prevents two unrelated histories from being mistaken for one.
tattoo
A permanent design made in the skin.
Tattoo came from Tahitian.
How tattoo reached English
oldest firstTahitian
tatau
‘Tattoo’
into English
English
tattoo
‘A skin design’
The story of tattoo
Related
The same spelling can hide two entirely different word families.