noun
message area; MA
A telecommunications term for a charging zone where calls are billed at a uniform rate; often abbreviated as MA.
単位料金区域（MA）は、市内通話料金が適用される地域を指します。
A message area (MA) refers to a region where local call rates apply.
Compound of 単位 (unit), 料金 (charge), and 区域 (area). The exact historical derivation is uncertain; the term is used in modern telecommunications.