English Dictionary

union bug

noun

(printing) A maker's mark imprinted on a work to show that it is sanctioned by members of a trade union. It is often a tiny elongated rhomboid containing and surrounded by, in minuscule typeface, identifying names and the union's local chapter number.

The union bug is a symbol used to indicate that a product or service was produced by workers who are members of a labor union.

意味（1）

(printing) A maker's mark imprinted on a work to show that it is sanctioned by members of a trade union. It is often a tiny elongated rhomboid containing and surrounded by, in minuscule typeface, identifying names and the union's local chapter number.

Printed matter circulated by the (US) Democratic Party inevitably displays a union bug.