ACROSTIC ETYMOLOGY

Acrostic poems have vertical words hidden in them
Coming from Latin acrostichis, this term was borrowed in the 1580s
Right before that, we can trace it to Greek akrostikhis.
One part of that is akros, which meant "outermost" or "at the end".
Second, the word stikhos meant "row" or "line"
Together, an acrostic is something connecting the outermost parts of the row.
If we derive akros from PIE, it's reconstructed to ak, meaning "sharp"
Certainly interesting, and stikhos is from steigh, "to stride".