Linear A Definition

An undeciphered writing system used in Crete from the 18th to the 15th century bc .
American Heritage

A Minoan script that was in use on Crete earlier than Linear B and has not yet been deciphered.

Webster's New World

A syllabary used to write the as-yet-undeciphered Minoan language, and an apparent predecessor to other scripts, such as Linear B.