1. A poem or series of lines in which certain letters, usually the first in each line, form a name, motto, or message when read in sequence.
2. See word square.

[French acrostiche, from Old French, from Greek akrostikhis : akron, head, end; see acromegaly + stikhos, line.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.