EKU

EKU - see Earliest Known Use.
Electric Eye - 1.) a device that employs a beam of light to facilitate more accurate perforation of stamps during the manufacturing process. 2.) the markings (see Electric Eye Dashes, Electric Eye Margin Line, ...

EKU - acronym for Earliest Known Use. (see above).
Embossing - the process of giving relief to paper by pressing it with a die. The result is a raised portion of the design.

EKU: The cover or piece that documents the earliest date on which a stamp or postal stationery item is known to be used. New discoveries can change an established EKU. The EKU for a classic issue may be after the official issue date.

EKU
Earliest known use. A designation for the earliest identified postmark on a stamp for which a first day of issue was not designated. [Back to top]
electric eye (EE) ...

Earliest known use (EKU): term applied to earliest date on which a stamp is recorded to have been used.
Earliest surviving letters: clay tablets in a cuneiform script, that was baked and hardened, then placed in clay envelope type containers.

Earliest Known Use (EKU)
The earliest date on which a stamp has been postally used. Many modern stamps have been released early and used on mail before the official first day of issue.

The earliest known use (EKU) of a stamp may or may not be the same as the first day of issue. This can happen in several ways: ...

Earliest Known Use (EKU) - The cover or piece that documents the earliest date on which a stamp or postal stationery item is known to be used.

They are not historic in the same sense of earliest known use (EKU) covers featuring classic stamps, which are worth a good deal of money.

See also: Stamp, Cover, First day, Earliest known use, Error