noun
non-standard-sized mail
Postal term for mail items that exceed the standard size or weight limits for regular mail, requiring different postage rates.
定形外郵便物は、定形郵便物より送料が高くなります。
Non-standard-sized mail costs more to send than standard-sized mail.
Standard-sized mail that fits within the size and weight limits for regular postage; 定形外郵便物 is the opposite, for items exceeding those limits.
Compound of 定形 (standard size), 外 (outside), and 郵便物 (mail item).